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By  Joseph  McCabe 

A  Candid  History  of  the 
Jesuits 

Life  of  Peter  Abelard 

Crises  in  the  History  of 
the  Papacy 

The  A  B  C  of  Evolution 

Evolution  of  Civilization 

Ice   Ages:    The    Story  of 
the  Earth's  Revolutions 

V/onders  of  the  Stars 


The 

A  B  C  of  Evolution 


By 

Joseph  McCabe 

Author  of  "The  Story  of  Evolution,"  ''Evolution  from  Nebula 
to  Man,"  "The  Evolution  of  Mind,"  etc. 


cgJ 


G.  P.  Putnam's  Sons 
New  York  and  London 
;rbe   ftnicFiet&ocfier  pteee 


r 


Copyright,  1920 

BY 

G.  P.  PUTNAM'S  SONS 


First  printing,  January,  152 1 
Second  printing,  March,  1924 


**04 


Made  in  the  United  States  of  America 


PREFACE 

During  several  years'  experience  of  lecturing  on 
Evolution  I  have  been  more  and  more  impressed  with 
the  need  of  a  new  primer  of  the  subject.  The  lecturer 
or  writer  on  Evolution  is  too  apt  to  think  that  the  ele- 
mentary stage  is  passed.  This  is  a  mistake.  The 
field  of  science  is  now  so  large  and  so  thoroughly  cut 
up  into  distinct  plots  that  a  man  or  woman  may  have 
quite  a  good  knowledge  of  one  section,  yet  need  ele- 
mentary assistance  on  a  general  subject  like  Evolu- 
tion. The  man  who  could  teach  me  much  about 
wireless  telegraphy  or  chemistry  asks  me  for  the  plain- 
est possible  instruction  on  Evolution.  Moreover, 
there  are  other  things  to  study  besides  science.  There 
are  art,  literature,  history,  and  political  economy.  And 
for  most  people  there  is  much  work  to  do,  and  little 
time  to  study  anything. 

Hence  I  quite  understand  the  demand  for  a  very 
clear,  elementary,  and  short  text-book.  There  are 
several  manuals  in  existence,  and  they  have  their 
merits ;  but  they  fail  in  one  or  other  respect  to  meet 
the  particular  need  I  have  in  mind.  Some  are  a  little 
out  of  date.  Some  are  too  large.  Some  are  not 
general  enough.    There  is  a  large  section  of  the  public 

iii 


iv  PREFACE 

that  would  like  to  have  a  quite  modern  and  quite 
simple  account  of  this  wonderful  thought  which  now 
runs  through  the  whole  of  our  culture.  They  want 
the  A  B  C  of  the  matter,  but  they  want  it  up-to-date, 
so  that  they  may  understand  what  scientific  men  are 
talking  about  to-day.  I  trust  that  this  little  work 
will  meet  their  wishes. 

J.  M. 


CONTENTS 

CHAPTER  PAGE 

I.  Evolution  the  Key  to  Nature  .  i 

II.  The  Evolution  of  the  Universe  .  ii 

III.  Life  in  the  Primitive  Ocean    .  .  22 

IV.  Land  Life  Begins     ....  36 
V.  In  the  Grip  of  an  Ice  Age       .  .  48 

VI.  The  Brontosaur  and  Its  Cousins  .  59 

VII.  The  Evolution  of  the  Flowers  .  71 

VIII.  The  Coming  of  the  Birds         .  .  82 

IX.  The  Triumph  of  the  Mammals  .  92 

X.  The  Origin  of  Man          .        .  .105 

XI.  Social  Evolution    .        .        .  .117 


^% 


The  A  B  C  of  Evolution 


CHAPTER  I 

EVOLUTION  THE  KEY  TO  NATURE 

If  you  want  to  understand  what  evolution  is,  and  why 
some  scientific  men — who  are  not  usually  poetic — 
have  compared  it  to  a  sun  rising  in  the  nineteenth 
century  to  illumine  the  darkness  of  nature,  try  to  put 
yourself  in  the  position  of  some  thoughtful  man  of 
the  days  of  George  IV.  There  was  already  quite  a 
respectable  science  in  those  days.  There  was  a 
Royal  Society.  There  were  geologists  and  chemists 
and  astronomers.  For  two  hundred  years  English- 
men of  great  ability  had  been  working  hard  to  attain 
the  kind  of  knowledge  which  we  call  ** science";  that 
is  to  say,  knowledge  based  as  carefully  a^  possible  on 
actual  observation. 

Yet  nature  as  a  whole,  and  myriads  of  separate 
things  in  nature,  were  so  dark  and  unintelligible  that 
we  may  really  say  that  they  awaited  the  rising  of  the 
sun.  Your  grandfather,  supposing  that  he  were  of  a 
thoughtful  turn,  would  ask  endless  questions  to  which 


2  EVOLUTION  THE  KEY  TO  NATURE 

science  could  give  no  answer.  Why  had  he  this  thin 
and  useless  coat  of  hair  on  his  body?  Why  was  his 
cat  so  like  a  tiger?  Why  did  miners  bring  petrified 
fish-bones  out  of  the  deepest  mines?  Why  was  the 
negro  black  and  the  Chinaman  yellow?  Why  was 
the  moon  cold,  the  sun  hot,  and  the  earth  between 
the  two?  Why  were  Englishmen  civilized  and 
Africans  not?  Why  had  flowers  different  colours? 
Why  was  there  such  an  immense  variety  of  animals  ? 
Why  were  there  tape-worms?  Why  had  the  shark 
no  bones?  Why  was  England  an  island?  Why  were 
there  fiords  in  Norway? 

You  could  fill  an  immense  book  with  questions  that 
could  not  be  answered  eighty  years  ago.  And,  apart 
from  the  fact  that  science  was  very  young  and  needed 
more  time,  all  these  things  were  obscure,  and 
threatened  to  remain  obscure,  because  one  single, 
simple  idea  had  not  yet  been  grasped.  That  idea  was 
to  be  the  starting  point  of  the  explanation  of  all  these 
and  hundreds  of  thousands  of  other  problems.  It  was 
this:  That  nature,  and  all  things  in  nature,  had 
grown,  during  tens  of  millions  of  years,  to  be  what 
they  were.  They  had  been  shaped  very  slowly  and 
gradually,  and  had  passed  through  numerous  earlier 
forms.     They  had  been  "evolved." 

The  word  "evolution"  is  the  Latin  word  for 
"unrolling."  Roman  books  were  written  on  parch- 
ment and  rolled  on  wooden  or  ivory  rods,  as  maps 
are  to-day.     Unrolling  one,  to  read  it,  was  "evolu- 


EVOLUTION  THE  KEY  TO  NATURE  3 

tion."  About  the  seventeenth  century  the  word 
began  to  be  used  in  English  for  the  "unrolling"  of 
the  scroll  of  history,  of  the  fates,  etc.;  then  the 
unrolling  or  expanding  of  anything  which  had  been, 
as  it  were,  folded  or  rolled  up.  The  body  "evolved" 
from  the  germ.  A  nation,  like  the  Romans,  evolved 
from  the  pastoral  tribe  which  history  represented  as 
its  first  stage. 

This  sort  of  evolution  was  going  on  so  obviously 
all  round  our  grandfathers  that  one  may  wonder  why 
they  did  not  perceive  that  it  was  a  law  of  nature. 
For  instance,  one  understood  the  striped  pole  outside 
the  barber's  shop  because  the  modern  barber  was 
evolved  from  the  barber-surgeon  of  the  Middle  Ages, 
who  used  to  put  this  red  pole,  with  a  white  bandaging 
tape  wound  round  it,  outside  his  shop  to  show  that 
he  bled  people.  One  understood  why  a  "gentle- 
man" had  two  buttons  on  the  back  of  his  coat  and 
the  workman  had  not,  because  they  were  evolved  from 
the  mediaeval  gentleman,  who  buttoned  his  sword 
there,  and  the  medieval  worker,  who  wore  a  smock, 
or  at  least  had  no  sword.  One  understood  the 
richness  of  the  English  language  because  it  had 
grown  out  of  a  mixture  of  the  tongues  of  the  British, 
Anglo-Saxons,  Danes,  Normans,  and  other  invaders. 
All  history  was  really  part  of  a  science  of  evolution. 
All  the  political  struggles  of  the  time  were  processes  of 
evolution.  Every  new  machine,  or  fashion  in  dress, 
or  improvement  in  the  home,  was  an  example    of 


4  EVOLUTION  THE  KEY  TO  NATURE 

evolution.  Our  fathers  were  painfully  familiar  with 
the  use  of  weapons;  and  every  museum  put  clearly 
before  their  eyes  "the  evolution  of  weapons." 

It  is  clear  to  us  now  that  they  needed  only  to 
believe  that  everything  had  similarly  grown,  and  they 
would  find  numbers  of  mysterious  things  lit  up.  If 
man  had  grown  from  a  non-human  type  of  animal, 
just  as  the  modern  Englishman  had  grown  out  of  the 
Druidic  Briton,  it  explained  any  number  of  puzzling 
features.  If  the  flowers  had  grown  to  be  what  they 
are,  and  some  had  grown  more  rapidly  than  others, 
one  understood  the  variety  of  nature.  If  the  hills 
and  fiords  and  valleys  had  been  under  the  shaping 
forces  of  nature  for  hundreds  of  thousands  of  years, 
the  face  of  the  earth  could  be  gradually  explained. 
The  English  race,  scattered  over  the  world,  was  easily 
understood.  It  had  a  common  root  in  mediaeval 
England,  and  its  later  growth  and  dispersion  might 
be  read  in  history.  Suppose  that  all  the  animals  and 
plants  of  the  world  likewise  had  a  common  root,  and 
had  been  growing  and  branching  out,  like  a  great 
oak,  for  millions  of  years !  There  was  the  great  key : 
a  key  that  would  unlock  the  secrets  of  stars,  and 
flowers,  and  oysters,  and  social  forms. 

It  is  hardly  necessary  to  recall  how  it  was  that 
until  recent  times  this  simple  fact  was  not  appre- 
ciated. In  many  previous  ages  thoughtful  men  had 
drawn  the  natural  conclusion  that  all  the  things  in 
the   world   had   grown.      Numbers   of   the    Greek 


EVOLUTION  THE  KEY  TO  NATURE  5 

thinkers  had  said  so.  The  chief  Roman  writer  on 
nature,  Lucretius,  had  repeated  it.  St.  Augustine 
himself,  in  his  best  days,  thought  that  all  the  different 
species  of  animals  and  plants  had  "grown"  out  of 
seeds  that  had  been  put  in  the  earth  at  the  begin- 
ning of  time.  The  wonderful  Italian  monk  of  the 
Middle  Ages,  Giordano  Bruno,  taught  evolution.  But 
the  fate  of  Bruno  reminds  us  why  it  was  that  so  few 
accepted  the  plain  truth  of  evolution,  which  had  been 
suggested  by  the  Greeks  2,500  years  ago.  It  was 
"heresy."  All  Europe  was  now  convinced  that  sun 
and  moon  and  stars,  oak  and  lily  and  wheat,  cat  and 
bird  and  man,  had  been  created  as  we  know  them. 

With  this  belief  science  was  bound  to  struggle. 
Scientific  men  naturally  wanted  scientific  explana- 
tions of  things,  if  it  were  possible.  In  a  sense  they 
wanted  to  conceive  nature  as  a  work  of  art:  a  statue 
that  had  been  slowly  carved  out  of  a  rude  block,  or  a 
wonderful  fabric  that  had  been  gradually  woven  on 
"the  looms  of  time."  If  they  could  discover  the 
chisels  which  had  carved  the  statue,  or  the  threads 
that  had  been  blended  in  the  fabric  of  nature,  it  was 
more  intelligible.  They  very  soon  learned  that 
nature  had  grown,  during  millions  of  years,  to  be 
what  it  is.  The  study  of  the  rocks,  which  was  very 
fairly  advanced  by  the  year  1840,  was  sufficient  to 
prove  this. 

The  rocks  are  the  vaults  of  the  great  living  family. 
When  they  were  opened  up,  in  the  eighteenth  and 


6  EVOLUTION  THE  KEY  TO  NATURE 

nineteenth  centuries,  it  was  quite  easy  to  see  that 
burials  had  been  going  on  for  tens  of  millions  of 
years.  And  it  was  noticed  that  the  deeper  you  went 
the  simpler  the  forms  became  and  the  more  they 
approached  each  other.  The  facts  themselves  sug- 
gested that  the  animal-forms  we  know  to-day,  so 
different  from  each  other  as  they  are,  had  common 
ancestors  in  the  past.  Life  was  a  great  many- 
branched  tree,  with  a  single  root  in  the  soil  of  "dim, 
remote  ages." 

Several  writers  had  suggested  this  before  Charles 
Darwin  became  convinced  of  it  in  1836,  but  that 
patient  and  gifted  naturalist  took  twenty  years  to 
work  out  his  theory  and  collect  facts  in  support  of  it, 
so  that  his  Origin  of  Species,  which  was  published  in 
1859,  was  irresistible.  One  set  of  scientific  men  after 
another  now  began  to  apply  the  principle  of  evolution, 
or  gradual  growth,  and  each  department  of  nature 
which  they  studied  was  lit  up  as  it  had  never  been 
before.  Sir  Isaac  Newton  had  traced  a  remarkable 
unity  in  lifeless  nature  when  he  discovered  the  law 
of  gravitation.  A  far  more  intimate  unity  was  now 
discovered,  both  in  living  and  lifeless  nature,  in  the 
light  of  the  new  truth. 

Everything  known  to  us  had  been  evolved.  From 
distant  suns  to  our  social  and  religious  institutions, 
from  diamonds  or  oceans  to  the  human  struggles  of 
to-day  and  the  ideals  of  to-morrow,  the  whole  contents 
of  the  known  universe  fell  into  one  grand  and  intel- 


EVOLUTION  THE  KEY  TO  NATURE  7 

ligible  scheme.  It  was  like  looking  down  upon  a 
hilly  region  in  the  early  morning,  when  the  summits 
of  the  hills  stand  out,  far  from  each  other,  but  a  mist 
lies  on  the  valleys  and  conceals  the  connections. 
Then  the  sun  rises,  and  the  entire  panorama  of  hill 
and  dale  becomes  a  connected  whole  before  your  eyes. 
Merely  recognizing  the  fact  that  nature  had  been 
evolved  had  that  effect  upon  man's  mental  picture 
of  it,  or  his  "science"  of  it. 

It  is  important  to  understand  this  clearly.  The 
mind  of  man  leaped  forward,  all  the  culture  of  the 
world  advanced  rapidly,  when  the  fact  of  evolution 
was  seen.  But  the  fact  of  evolution  is  a  different 
thing  from  the  methods  or  agencies  of  evolution.  Even 
if  we  knew  nothing  of  the  agencies  which  brought 
about  evolution,  the  fact  would  remain  a  most 
important  and  permanent  gain  to  every  branch  of 
knowledge.  No  scientific  man  in  the  world  now 
doubts  it,  or  has  done  so  for  several  decades  past. 
He  would  as  soon  think  of  doubting  the  existence 
of  the  sun.  All  the  controversies  which  puzzle  the 
reader  of  larger  works  on  evolution  relate  to  the 
agencies  or  machinery  of  evolution,  not  to  the  fact. 
To  say  that  things  "grow"  is,  of  course,  only  a 
childish  expression.  When  a  geranium  is  "growing" 
in  a  pot  there  is  a  most  wonderful  machinery  in  it 
developing  the  stems  and  leaves  and  flowers.  For 
the  whole  of  nature  the  machinery  is  colossal,  and  it 
may  be  a  long  time  before  it  is  really  known.     I  will 


8  EVOLUTION  THE  KEY  TO  NATURE 

try  to  make  it  clearer  that  evolution  is  a  great  dis- 
covery in  spite  of  all  the  disputes  about  its  machinery. 

Evolution  is  not  a  "force"  or  an  agency  that  does 
things.  Strictly  speaking,  ''forces"  and  "laws"  are 
not  agencies  that  do  things,  though  we  often  speak 
of  them  as  if  they  were.  ^  But  evolution  is  not  a  force 
or  energy;  and  it  is  a  "law"  only  in  the  strict  sense. 
It  is  an  invariable /flc^.  It  is  the  fact  of  the  unrolling 
of  the  scroll,  not  the  hand  that  unrolls  it.  So  there 
may  be  perfect  certainty  about  the  fact  of  evolution, 
and  complete  uncertainty  about  the  machinery  or 
agencies  at  work.  Some  say  that,  if  this  is  so,  evolu- 
tion explains  nothing.  There  could  not  be  a  greater 
mistake.  It  is  literally  true  that  the  whole  of  nature 
is  lit  up  when  we  recognize  the  fact  that  it  was  evolved. 
Any  thoughtful  person  can  see  how  intelligible  man 
and  his  institutions  become  if  we  recognize  that  they 
were  evolved.  Hundreds  of  features  which  puzzled 
us  before  are  now  understood.  This  will  become 
quite  clear  in  the  course  of  the  book. 

Now,  Darwinism  is  not  evolution.  It  is  a  theory  of 
the  way  in  which  the  evolution  of  living  things  was 
brought  about:  a  theory  of  the  machinery  of  a  part 
of  nature.  Even  if  Darwin's  theory  comes  to  be  re- 
jected, his  magnificent  service  in  getting  the  fact  of 

^  Force  is  an  abstract  word  used  in  physics  to  express  certain 
features  of  work  or  movement.  It  is  matter  or  ether  that  really 
works.  Law — a  "law  of  nature" — is  also  an  abstract  word  to 
express  the  fact  that  things  do  actually  move  or  behave  on  certain 
definite  lines. 


EVOLUTION  THE  KEY  TO  NATURE  9 

evolution  recognized  makes  him  immortal  in  science. 
His  theory  is,  as  a  matter  of  fact,  very  much  disputed. 
Darwin  looked  about  him,  and  saw  that  far  more 
living  things  are  born  than  nature  can  sustain  or  the 
earth  hold .  He  saw  that  this  caused  a  great ' '  struggle 
for  life,"  and  that  the  ''fittest" — those  best  equipped 
to  meet  their  particular  struggle — survived.  Nature, 
in  other  words,  ** selected"  the  fittest;  and  so  his 
theory  is  called  "natural  selection."  Take  the  hawk. 
Its  success  in  life  depends  on  keenness  of  eye  and 
strength  of  wing.  Every  time  a  few  hawks  are 
hatched  some  will  have  slightly  better  eyes  or  wings 
than  others.  They  have  more  chance  of  surviving; 
and  they  will  hand  on  their  improved  eyes  and  wings 
to  the  next  generation.  In  the  course  of  hundreds  of 
thousands  of  years  these  minute  improvements  at 
each  birth  will  have  brought  about  a  much  higher 
type  of  bird.  "Natural  selection,"  he  said,  was  the 
agency  of  evolution. 

That  this  process  does  actually  go  on  throughout 
nature,  and  even  in  our  social  and  economic  order, 
any  person  can  see ;  but  it  is  now  disputed  if  it  is  the 
general  machinery  of  evolution.  The  pioneer  in  any 
new  field  of  research  generally  makes  some  mistakes. 
Some  now  think  that  the  embryological  machinery, 
not  the  destructive  or  "selective"  work  of  nature,  is 
the  great  agency.  Some  think  that  the  gradual 
strengthening  during  a  long  period  of  small  improve- 
ments in  each  generation  is  not  a  satisfactory  explana- 


10  EVOLUTION  THE  KEY  TO  NATURE 

tion.  They  believe  that  there  are  sometimes  very 
marked  advances  at  a  single  birth  (which  they  call 
"  mutations  "  =  changes) ,  and  it  is  these  which  are  the 
great  agency  of  progress.  So  you  get  three  chief  types 
of  theory,  and,  passing  over  other  shades  of  opinion 
as  unsuitable  for  this  small  work,  we  may  express 
them  thus : 

1.  Darwinism.  Progress  is  due  to  the  selection 
by  nature  of  the  fitter  to  survive.  This  really  means 
the  destruction  by  nature  of  the  less  fit  to  survive, 
so  that  strength,  weapons,  senses,  etc.,  are  gradually 
improved,  just  as  we  gradually  improve  our  sheep 
and  cattle.  Few  now  hold  that  this  is  as  complete 
an  explanation  as  Darwin  thought. 

2.  Weismannism.  That  the  action  of  nature  is 
secondary,  and  the  advances  of  animals  and  plants 
are  determined  in  the  germ  (or  "germ-plasm"). 
Progress  is  gradual,  by  small  improvements  in  each 
generation.  This  theory  of  Professor  Weismann  is 
not  held  as  much  as  it  was  twenty  years  ago. 

3.  Mutationism  or  Mendelism.  Small  changes  or  im- 
provements in  offspring  would  be  lost  or  "swamped." 
Large  changes,  in  which  the  offspring  differs  consider- 
ably from  the  parent,  often  occur,  and  these  make 
new  species.  This  theory  provides  a  very  elaborate 
scheme  of  the  elements  of  heredity.  It  takes  its  name 
from  Abbot  Mendel,  but  is  chiefly  due  to  Professor 
Hugo  de  Vries.  It  has  to  meet  many  difficulties,  and 
is  far  from  generally  received. 


CHAPTER  II 

THE  EVOLUTION   OF  THE   UNIVERSE 

The  moment  we  begin  to  apply  the  principle  of 
evolution  we  see  the  truth  of  the  simple  statements  I 
have  asked  the  reader  to  bear  clearly  in  mind.  The 
first  is  that  the  fact  of  evolution  is  the  greatest  dis- 
covery the  mind  of  man  ever  made,  no  matter  what 
controversies  there  may  be  about  its  machinery.  The 
second  is  that  Charles  Darwin  perceived  a  truth  of 
the  greatest  importance  when  he  discovered  *  *  natural 
selection."  Even  if  you  live  in  a  village,  you  have 
only  to  open  your  eyes  to  see  the  reality  of  natural 
selection.  You  see  the  struggle  of  a  litter  of  young 
pigs  for  food;  the  struggle  of  a  swarm  of  grubs  that 
hatch  from  a  caterpillar's  eggs;  the  struggle  of  men 
for  employment,  of  shopkeepers  for  prosperity.  The 
weakest,  for  the  particular  struggle,  "go  to  the  wall." 
The  fittest,  for  the  particular  struggle  (not  necessarily 
the  best  or  the  strongest),  survive.  That  is  natural 
selection. 

Now,  this  may  not  prove  to  be  an  explanation  of 
everything  in  living  nature.  There  are  certainly 
many  features  of  animals  and  plants  that  it  does  not 
easily  explain.    In  any  case,  it  does  not  go  far  enough, 

II 


12  THE  EVOLUTION  OF  THE  UNIVERSE 

because  it  throws  no  light  on  the  living  machinery 
(the  embryonic  machinery)  which  causes  the  varia- 
tions at  birth.  Also,  it  may  be  true  that  new  species 
are  often  formed  by  sudden,  large  changes  at  birth; 
though  few  instances  of  this  are  positively  known. 
However  that  may  be,  Darwin  pointed  out  a  truth, 
and  we  now  know  that  it  was  in  some  ways  more  far- 
reaching  than  he  thought.  He  was  a  biologist,  and 
was  concerned  only  with  living  things.  We  know  to- 
day that  this  truth  more  or  less  embraces  the  entire 
universe. 

What  we  call  the  ''universe"  to-day  is  a  collection 
of,  perhaps,  2,000,000,000  suns  or  stars,  to  which  our 
sun  or  star  belongs.  No  one  can  possibly  count 
them,  as  the  greater  part  of  them  are  represented 
only  by  very  faint  points  of  light  on  photographic 
plates  which  have  been  exposed  for  many  hours  in 
giant  telescopes.  They  crowd  together,  making  little 
clouds  of  light  on  the  plates;  and  we  can  merely 
roughly  estimate  that  there  are  about  2,000,000,000 
of  them  in  the  system  or  collection  to  which  our  sun 
belongs.  No  'doubt  many  of  them  have  planets,  as 
our  sun  has.  No  doubt  there  are  living  populations, 
with  ideas  and  institutions,  on  many  of  these  planets. 
All  these  are  contents  of  our  universe.  There  are 
also  incompletely  developed  stars,  dead  stars,  and 
masses  of  loose  material  that  may  one  day  form  stars. 
That  is  our  universe. 

I  keep  repeating  the  word  *'our"  because  it  is 


THE  EVOLUTION  OF  THE  UNIVERSE  13 

to-day  an  open  question  whether  there  are  "other 
universes  than  ours."  Many  people  think  that  the 
word ' '  universe  * '  means  the  * '  whole ' '  of  existing  things , 
and  the  word  is  generally  used  in  that  sense  outside 
of  modern  astronomy.  But  that  is  not  the  literal 
meaning  of  it,  ^  and  astronomers  choose  to  call  a  vast 
collection  of  stars  which  form  one  immense  family — 
that  is  to  say,  which  control  each  other's  movements 
by  gravitation — a  universe.  There  may  be  other 
great  systems  of  stars  which  are  so  far  from  ours 
that  they  are  practically  independent.  Many  dis- 
tinguished astronomers  to-day  think  that  we  do 
dimly  see  such  "island  universes,"  as  they  call 
them,  shining  faintly,  as  blots  of  light,  on  the  dark 
background  of  space.  I  will  say  more  about  this 
presently. 

Our  universe,  then,  is  a  collection  of  hundreds,  and 
possibly  thousands,  of  millions  of  worlds;  if  we  call 
each  star  and  its  planets  a  world.  They  are  separated 
by  millions  of  miles  of  space  from  each  other.  They 
are  stupendous  globes  of  white-hot  metal  and  gas,  at 
a  temperature  of  something  between  3,000°  C.  (red 
stars)  and  30,000°  C.  (bluish-white  stars).  Our  sun, 
860,000  miles  in  diameter,  is  a  fair  average,  or  a  little 
above  the  average,  in  size,  as  far  as  we  know.  But 
some  are  so  much  more  intense  in  their  light  that, 

^The  Latin  Word  "universum"  is  often  said  to  mean  "the 
unity  of  all  things";  but  it  does  not  contain  the  word  "all."  It 
means  a  unified  system. 


14  THE  EVOLUTION  OP  THE  UNIVERSE 

whatever  allowance  we  make  for  higher  temperature^ 
they  must  be  far  larger.  We  cannot  measure  the  size 
of  stars,  but,  when  the  distance  is  known,  we  can 
measure  their  brilliance.  Professor  Pickering  has 
recently  calculated  that  the  star  Rigel,  in  the  con- 
stellation Orion,  gives  out  87,000  times  as  much  light 
as  our  sun;  and  our  sun  has  a  temperature  of  7,000°  C. 
at  its  metallic  surface,  and  possibly  1,000,000°  C.  in 
its  interior.  The  star  Canopus  is  said  to  be  equal  in 
light-power  to  50,000  suns  like  ours. 

Here  we  have  a  first  suggestion  of  evolution  in  our 
universe.  The  colours  of  the  stars  may  have  various 
causes,  but  in  the  main  they  are  determined  by 
temperature.  Some  are  blue,  some  white,  some  yellow 
(like  our  sun),  and  some  red.  That  sounds  like 
globes  of  metal  cooling  down ;  and  the  astronomer  now 
has  instruments  by  which  he  can  fully  confirm  this 
first  impression.  The  stars  are  masses  of  white-hot 
metal,  surrounded  by  flaming  gas,  which  rise  up  to  a 
certain  highest  point  of  temperature  (probably  about 
30,000°  C.  at  the  surface)  and  gradually  cool  down 
until  they  cease  to  give  out  light.  By  an  instrument 
called  the  spectroscope — the  most  wonderful  instru- 
ment ever  invented  by  man — we  can  analyse  their 
light  and  trace  the  different  stages  of  their  cooling.^ 

^  I  wish  to  be  brief  and  simple  here,  but  the  reader  who  would 
like  to  know  more  about  this  fascinating  branch  of  the  science  of 
evolution  will  find  the  material  of  this  chapter,  fully  and  clearly 
developed,  in  my  recent  work,  The  End  of  the  World  (Watts;  6s. 
6d.  net ;  with  many  illustrations) , 


THE  EVOLUTION  OF  THE  UNIVERSE  15 

The  millions  of  stars  in  the  sky  are  of  different  ages. 
Some  are  in  the  prime  of  life.  Some  (like  our  own) 
are  beyond  middle  age.  Large  numbers— astronomers 
now  generally  hold — died  long  ago. 

This  is  one  half,  the  latter  half,  of  the  evolution 
of  worlds.  The  next  step  is  to  trace  the  first  half, 
to  discover  their  origin  and  early  stages.  Here 
there  is  a  good  deal  of  dispute,  but  we  may  choose 
a  very  clear  starting  point  which  is  admitted  by 
all.  If  you  leave  your  room  full  of  fine  dust  at 
night,  you  will  find  all  this  gathered  together  on 
the  floor  in  a  layer  the  next  morning.  The  floor 
(or  the  earth)  "attracts"  it,  we  say.  Now,  sup- 
pose an  enormous  cloud  of  this  dust  were  in 
space,  millions  of  miles  away  from  any  solid  globe 
to  attract  it.  Suppose  this  cloud  were  millions  or 
billions  of  miles  in  extent,  and  it  consisted  of  a 
mixture  of  particles  of  all  the  metals  and  gases.  How 
wotdd  it  behave? 

We  should  say  that  if  the  dust  were  quite  evenly 
distributed,  and  nothing  entered  it  to  disturb  it,  it 
might  remain  as  a  cloud  for  indefinite  ages.  But,  as 
a  matter  of  fact,  the  chances  of  such  a  cloud  being 
quite  equally  distributed  are  very  slight.  There 
would  be  sure  to  be  some  parts  denser  than  others. 
Then  we  know  what  would  happen.  These  thicker 
parts  or  centres  would  begin  to  "attract"  the  dust 
from  all  round  them.  Even  if  there  were  no  denser 
centres  to  begin  with,  there  soon  would  be.     As  we 


i6  THE  EVOLUTION  OF  THE  UNIVERSE 

know  from  our  shooting-stars,  which  are  fragments 
of  metal  (from  grains  to  large  blocks)  that  shoot 
rapidly  into  our  atmosphere  at  night,  and  are  burned 
up  by  friction,  soace  is  far  from  empty.  Countless 
myriads  of  these  solid  particles  or  blocks  travel 
through  it  at  a  great  speed.  The  "ocean  of  ether" 
is  as  full  of  them  as  the  sea  is  of  fishes.  A  great 
cloud  of  dust  billions  of  miles  in  extent  would  capture 
countless  numbers  of  them. 

So  there  would  be  sure  to  be  denser  centres  in  our 
imaginary  dust  cloud.  These  would  draw  the  sur- 
rounding dust  by  the  same  law  of  gravitation  as  the 
earth  gathers  the  dust  in  your  room.  They  would 
grow  larger  and  denser.  The  spaces  between  the 
thick  centres  would  grow  thinner  and  thinner.  More- 
over, as  these  centres  would  be,  so  to  speak,  sus- 
pended in  space,  they  would  draw  particles  freely 
from  all  sides,  and  would  take  the  shape  of  large 
loose  globes.  If  you  imagine  this  going  on  for  mil- 
lions of  years,  you  see  at  once  that  in  the  end  prac- 
tically all  the  dust  of  the  cloud  will  be  gathered 
into  so  many  large  globes,  with  great  empty  spaces 
between  them.  You  will  also  see  that  the  heavier 
particles,  the  metals,  will  go  to  the  centre,  and  the 
lighter  particles,  the  gases,  will  remain  at  the  fringe. 
You  will  have  gaseous  atmospheres  round  globes  of 
metal. 

The  mathematician  can  tell  us  a  good  deal  more 
about  what  would  happen.     We  understand  him  well 


THE  EVOLUTION  OF  THE  UNIVERSE  17 

enough  when  he  says  that  this  coming  together,  or 
condensation,  of  the  particles  of  dust  would  cause 
heat.  Compression  always  causes  heat.  And  when 
you  are  thinking  of  a  mass  of  metal  dust  weighing 
trillions  of  tons,  as  a  star  does,  the  heat  will  in  the 
end  be  prodigious.  The  concentrated  dvist  would 
become  a  star.  We  need  only  say  further  that  these 
great  centres  of  fiery  concentrated  dust  would  tend  to 
turn  round  on  their  axes;  and  that,  although  they 
were  tens  of  millions  of  miles  apart,  they  would  be 
sucked  into  each  other  and  destroyed  unless  they 
travelled  rapidly  through  space  in  orderly'  paths.  At 
first,  we  suppose,  they  would  be  a  disorderly  crowd. 
Then  ** natural  selection"  would  set  in.  The  small 
irregular  masses  would  be  sucked  into  the  larger. 
No  doubt  some  of  the  giant  suns  I  have  mentioned 
have  fed  on  others  in  this  way.  In  the  end  the  great 
cloud  of  dust  would  be  a  collection  of  fiery  globes 
travelling  in  circular  paths  at  a  safe  distance  from 
each  other. 

That  is  how  we  understand  the  origin  of  stars. 
Such  clouds  do  exist  in  the  heavens  in  great  numbers. 
Astronomers  call  them  *' nebulae,"  which  is  the  Latin 
for  clouds.  They  already  have  heat  enough  to  be 
visible  to  us.  One  large  class  of  them,  which  we  call 
the  "spiral  nebula,"  are  much  disputed.  Some 
think  that,  as  I  said  on  an  earlier  page,  they  are 
separate  imiverses  at  a  prodigious  distance  from  us. 
I  do  not  share  this  view.     Most  astronomers  believe 


1 8  THE  EVOLUTION  OF  THE  UNIVERSE 

that  the  spiral  nebula  are  masses  of  glowing  metal 
being  formed  into  worlds.  They  are  nebulae  in  an 
advanced  stage  of  evolution.  Other  nebulae  are 
plainly  proved  by  the  spectroscope  to  be  clouds  of 
billions  of  miles  of  glowing  gas.  At  all  events,  our 
"cloud"  is  not  an  imaginary  thing  at  all.  Turn  it 
into  the  Latin  *' nebula,"  and  there  are  about  200,000 
of  them  known  to  us. 

Apart  from  a  few  recent  speculations,  which  do  not 
seem  likely  to  be  accepted,  the  general  belief  is  that 
the  stars  were  made  by  the  gathering  together  into 
solid  globes  of  vast  loose  clouds  of  material  in  this 
way.  Whether  the  material  was  gas,  or  solid  particles, 
or  both  mixed  together,  is  disputed ;  and  we  need  not 
go  into  the  point.  ^  How  far  metals  like  radium  add 
to  their  heat  is  also  disputed.  These  things  must  be 
studied  in  larger  books.  The  general  truth  is  enough 
here.  The  stars  are  evolved  from  great  clouds  of 
loose  matter  by  condensation. 

Sometimes  you  read  in  the  papers  that  a  "new 
star"  has  appeared  in  the  heavens.  It  is  not  thought 
that  this  is  the  ordinary  birth  of  stars.  They  grow, 
and   die    down,    too   rapidly.     The   life   of  a   star, 

^  Some  may  care  to  have  a  word  on  these  disputes.  There  are 
three  chief  theories.  The  Nebular  Hypothesis  conceives  the  cloud 
as  mainly  of  gas.  The  Msteoritic  Hypothesis  thinks  the  starting 
point  was  an  immense  swarm  of  meteors.  The  Plantesimal  Hypo- 
thesis takes  as  its  starting  point  a  vast  cloud  of  solid  particles,  and 
these  are  supposed  to  have  come  from  the  ripping  open  (by  another 
star)  of  a  dead  sun. 


THE  EVOLUTION  OF  THE  UNIVERSE  19 

normally,  must  be  hundreds,  if  not  thousands,  of 
millions  of  years.  Of  course,  the  great  sudden  blaze 
which  we  call  a  new  star  is  a  blaze  of  white-hot  gas; 
not  the  star  itself.  Still,  these  things  seem  to  be 
"accidents."  A  few  think  that  two  stars  have  come 
into  partial  collision — "grazed"  each  other,  so  to  say. 
If  two  masses  of  metal,  each  weighing  trillions  of 
tons  and  travelling  at  a  hundred  or  more  miles 
a  second,  were  to  do  this,  we  would  certainly  expect 
a  terrific  "blaze."  But  collisions  must  be  very  rare, 
and  new  stars  are  frequent.  Probably  a  dead  or 
invisible  star  has  rushed  into  one  of  the  great  dust 
clouds  (nebulae)  and  been  raised  to  white  heat,  in 
part,  by  friction.  Whatever  be  the  real  explanation, 
the  fact  is  impressive.  The  millions  of  stars  of  our 
universe  are  living,  dying,  and  being  born  again  all 
round  us. 

Modern  science  goes  a  step  further  than  this. 
Here  I  am  going  to  say  something  which  is  by  no 
means  settled,  but  the  speculation  is  so  vast  and 
interesting,  and  gives  such  a  wonderful  unity  to 
the  evolution  of  the  universe,  that  it  cannot  be 
omitted. 

Everybody  now  knows  that  a  mysterious  some- 
thing called  "ether"  runs  from  end  to  end  of  the 
universe,  and  passes  through  the  most  solid  matter 
that  we  know.  The  stars  are  like  great  sponges  in 
an  ocean  of  ether.  It  contains  those  other  "island- 
universes"  (if  they  are  such)  of  which  I  spoke,  as 


20  THE  EVOLUTION  OF  THE  UNIVERSE 

well  as  ours,  or  else  their  light  woxild  not  reach  us. 
What  if  all  our  stars  and  planets  and  nebulas — all 
the  matter  of  the  universe — were  evolved  out  of  this 
ether !  Clearly  this  is  one  of  the  greatest  and  most 
comprehensive  ideas  that  physical  science  ever  gave 
to  man. 

.  There  is  now  very  strong  reason  to  believe  this. 
Since  the  discovery  of  radium,  and  all  the  other  dis- 
coveries to  which  this  led,  our  scientific  men  are  con- 
vinced that  the  atom  of  matter  is  built  of  very  minute 
centres  of  energy  in  ether  (electrons).  The  simplest 
atom  may  contain  more  than  a  thousand  of  them, 
whirling  round  at  speeds  approaching  100,000  miles  a 
second.  The  atoms  of  the  heavier  metals  contain 
hundreds  of  thousands  of  them.  The  atoms  are 
orderly  "systems"  of  electrons,  just  as  universes  are 
orderly  systems  of  stars.  And  it  is  probable  that 
natural  selection  has  been  at  work  in  checking  the 
evolution  of  both  systems:  the  one,  the  atom,  so 
small  that  trillions  would  go  into  a  pin's  head;  the 
other,  the  universe,  thousands  of  billions  of  miles 
in  extent.* 

Here,  then,  we  have  the  answer  to  the  last  ques- 
tion: Where  did  the  matter  which  makes  the  stars 
come  from?  Apparently  from  ether.  Where  did 
the  ether  come  from?  We  have  no  reason  to  sup- 
pose that  it  came  from  anywhere.  It  may  be  the 
fundamental  reality,  from  the  bosom  of  which 
matter  rises,  to  form  stars  which  glow  for  hundreds 


THE  EVOLUTION  OF  THE  UNIVERSE  21 

of  millions  of  years  and  then  die,  to  be  born  and  glow 
again.  ^ 

I  What  about  Einstein's  theory,  which,  some  tell  you,  does  not 
admit  ether?  As  a  matter  of  fact,  it  admits  a  different  kind  of 
ether,  in  which  light  does  not  travel  in  straight  lines,  and  it  gives 
a  new  idea  of  gravitation.  Einstein's  theory  cannot  be  popularly 
explained,  as  every  scientist  who  has  tried  to  do  it  admits.  The 
best  attempts  are  an  article  by  Sir  Oliver  Lodge  in  the  Nineteenth 
Century,  December,  1919,  and  an  article  by  Professor  Eddington 
in  the  Contemporary  Review  for  the  same  month.  It  is  a  matter 
of  the  highest  mathematics,  and,  even  if  it  were  ever  proved 
(which  is  doubtful),  it  will  not  modify  the  ordinary  teaching  of 
science  as  much  as  some  say. 


CHAPTER  III 

LIFE  IN  THE  PRIMITIVE  OCEAN 

From  this  broad  picture  of  the  universe  we  must  now 
come  down  to  our  little  earth,  and  study  the  evolution 
of  life  on  it.  There  used  to  be  writers  who  told  us 
how  we  were  ** dwarfed"  by  the  vastness  of  the 
universe.  It  really  makes  no  difference  whatever  to 
us  how  vast  the  universe  is.  We  remain  just  the 
same  size,  however  much  the  universe  grows.  Then 
there  were  writers  who  tried  to  console  us  by  saying 
that  probably  we  were  the  only  living  inhabitants  of 
the  universe.  No  man  of  science  would  now  entertain 
that.  We  cannot  prove  that  there  is  life  anywhere 
except  on  the  earth;  but  we  will  study  the  develop- 
ment of  the  earth  and  the  life  on  it,  and  we  shall 
realize  that  the  same  t?iing  has  probably  happened  in 
countless  parts  of  the  universe. 

I  spoke  of  a  great  dust  cloud  which  might  condense 
into  patches,  and  these  in  turn  into  stars.  Now,  in 
each  patch,  or  region  of  concentration,  there  are  sure 
to  be  irregularities.  Some  parts  will  be  denser  than 
others.  The  dust  will,  therefore,  not  all  be  drawn  to 
the  central  part.  Some  will  gather  round  the  other 
denser  centres.     In  other  words,  the  last  result  will 

22 


LIFE  IN  THE  PRIMITIVE  OCEAN    23 

be  a  great  central  globe  and  a  number  of  smaller 
globes  (or  planets)  connected  with  it. 

These  smaller  globes  would,  of  course,  be  sucked 
by  gravitation  into  the  central  globe  unless  they 
moved  round  it  at  a  great  speed.  There  are  several 
ways  in  science  of  showing  how  this  circulation  of 
the  planets  round  the  sun  might  be  caused,  but  they 
are  too  advanced  for  this  little  primer.  If  the  reader 
will  look  at  the  photograph  of  a  spiral  nebula  in  some 
astronomical  book,  he  will  see  the  fiery  matter  con- 
densing into  a  large  central  sun  and  a  large  number 
of  smaller  fiery  masses  all  round  it.  We  know  that 
they  are  moving  round  it.  The  whole  structure  is 
turning  round. 

But  how  do  the  planets  come  to  follow  orderly 
paths  round  the  central  sun,  at  such  distances  and 
such  speeds  that  the  system  may  last  for  millions  of 
years?  Natural  selection  gives  the  answer.  At  first 
there  were  probably  far  more  planets  circling  round 
our  sun  than  there  are  now.  Those  which  followed 
unsuitable  paths  were  drawn  in  by  the  others  or  by 
the  sun  until  only  the  "fittest"  survived.  Our  eight 
planets  are  the  survivors  of  a  mighty  struggle  for  life. 

We  have  every  reason  to  suppose  that  the  other 
stars  were  formed  in  the  same  general  way  as  our 
sun.  It  is  therefore  probable  that  they  have,  unless 
there  v^ere  special  conditions,  planets  of  their  own. 
These  planets  are  made  of  the  same  material  as  ours. 
The  spectroscope  can  tell  us  what  even  the  most 


24    LIFE  IN  THE  PRIMITIVE  OCEAN 

distant  star  in  the  universe  is  made  of,  and  it  reports 
to  us  that  much  the  same  material  is  found  throughout 
the  whole  universe,  and  even  in  the  universes  beyond 
(if  there  are  any) .  When  you  have  the  same  material, 
following  the  same  general  laws,  you  naturally  expect 
results  of  substantially  the  same  nature.  The  metals 
would  keep  to  the  centre,  and  form  solid  globes.  The 
free  gases  would  remain  at  the  fringe,  and  form  atmos- 
pheres and  oceans.  This  is  the  reason  why  men  of 
science  regard  it  as  highly  probable  that  there  are 
countless  planets  with  living  populations.  We  have 
no  reason  to  suppose  that  our  earth  was  made  in 
any  special  manner.  There  are  probably  globes 
in  all  parts  of  the  universe  with  the  same  condi- 
tions of  life:  chemicals,  air,  water,  and  a  certain 
temperature. 

But  we  must  study  the  making  of  our  earth  a  little 
more  closely.  Originally,  as  I  said,  it  was  one  of 
many  fiery  globes  which  circled  round  the  sun.  They 
gradually  cooled.  The  planet  Mars,  being  very  much 
smaller  than  the  earth,  cooled  before  it.  That  is  why 
we  suppose  that,  if  there  is  life  on  Mars  (we  are  not 
quite  sure  of  its  conditions),  it  began  before  life  on 
the  earth,  and  is  probably  more  advanced.  However, 
our  earth  gradually  cooled,  and  at  length  the  oxygen 
and  hydrogen  gases  in  its  atmosphere  were  able  to 
unite  and  form  water.  But  the  earth  was  still  red-hot. 
Water  could  not  settle  on  its  surface.  So  the  whole 
mass  of  water  which  now  forms  our  oceans  then 


LIFE  IN  THE  PRIMITIVE  OCEAN    25 

existed  in  a  state  of  cloud  or  steam  in  the  atmosphere. 
The  earth  was  still  a  fiery  metal  globe,  surrounded 
by  a  tremendous  shell  or  mantle  of  steam.  That 
is  how  we  find  the  planets  Jupiter  and  Saturn  to-day. 
They  are  so  large  that  they  have  not  cooled  down  as 
far  as  the  earth.  They  are  red-hot  at  the  surface, 
and  all  that  we  see  of  them  is  the  great  mantle  of 
cloud  or  steam  that  surrounds  them.  You  see,  every 
feature  of  our  solar  system  is  just  as  we  should  expect 
to  find  it  on  the  theory  of  evolution  which  I  gave  in 
the  last  chapter. 

Under  a  great  canopy  of  moisture  like  this,  the 
metal  surface  of  the  earth  might  remain  molten  until 
it  sank  to  about  800°  C. ;  but  its  heat  was  being 
discharged  into  space  all  the  time,  and  its  temperature 
sank  steadily.  It  was,  remember,  a  block  of  iron 
cooling  down;  or,  rather,  it  was  a  mass  of  molten 
iron,  like  the  liquid,  glowing  stuff  you  may  have  seen 
in  a  furnace.  As  the  temperature  sank  the  steam 
would  approach  closer  to  the  surface,  and  at  last 
would  be  able  to  settle  as  water.  This  would,  of 
course,  take  a  long  time.  At  first  the  water  would 
boil,  and  be  blown  back  in  the  form  of  steam.  This, 
however,  would  hasten  the  cooling  of  the  earth,  and 
the  time  soon  came  when  the  surface  of  the  globe 
was  covered  with  a  boiling  ocean.  It  was  not  at  first 
salt  water.  The  salts  of  the  sea  have  been  gradually 
washed  out  of  the  rocks.  But  as  the  primitive  atmos- 
phere was  very  far  from  pure,  the  waters  which  settled 


26    LIFE  IN  THE  PRIMITIVE  OCEAN 

on  the  earth  would  also  contain  great  quantities  of 
acids  and  chemicals. 

Here,  then,  we  have  three  features  of  the  earth 
explained:  its  molten  interior,  its  solid  crust,  and  its 
oceans.^  A  globe  of  molten  metal  naturally  cools 
first  at  its  surface,  and  forms  a  crust  or  "slag,"  as 
molten  iron  does  in  the  foundry.  It  is  now  at  least 
a  hundred  million  years,  and  may  be  very  much  more, 
since  the  earth  began  to  cool.  The  solid  crust  has 
become  from  fifty  to  seventy-five  miles  in  thickness, 
and  the  great  mass  inside  remains  at  a  terrific  tempera- 
ture. The  pressure  is  too  great  to  allow  it  to  be  fluid, 
but  there  are  leaks  and  irregularities  in  the  crust,  and 
at  times  it  oozes  through  as  white-hot  lava.  There 
you  have  the  explanation  of  volcanoes,  and  partly  of 
earthquakes. 

At  first  the  crust  would  be  a  fairly  equal  scum  or 

slag  all  round  the  globe,   and  the  ocean  would  be 

fairly  equally  distributed  over  it.     At  the  most  a  few 

ridges  of  land  might  peep  out  of  the  hot  ocean.     But 

there  would  be  for   ages,   probably  for  millions  of 

years,   a  mighty  battle  between  the  crust  and  the 

molten  matter  below  it.     In  cooling,  the  surface  or 

crust  would  naturally  shrink.      The  skin,  so  to  say, 

would  always  tend  to  be  too  small  for  the  globe,  and 

*  I  ought  to  warn  the  reader  that  many  geologists  now  follow 
the  Planetesimal  Hypothesis,  which  I  mentioned  on  p.  i6.  Ac- 
cording to  this,  the  earth  was  formed  with  less  heat,  and  was 
never  all  molten.  The  accoimt  I  am  following  is  the  one  generally 
received,  and  most  probably  correct. 


LIFE  IN  THE  PRIMITIVE  OCEAN    2^ 

would  burst.  Then  the  molten  masses  below  would 
pour  up  and  over  the  crust.  This  would  go  on  for 
long  ages,  until  the  crust  was  thick  enough  to  confine 
the  fiery  giant  below  it.  That  is  why  we  find  the 
earliest  rocks,  which  represent  half  the  life  of  the 
earth,  mainly  volcanic.  When  the  crust  had  set  firm, 
the  great  process  of  wearing  down  the  rocks  would 
start,  and  the  sand  and  fragments  would  begin  to 
form  our  "sedimentary"  rocks  at  the  bottom  of 
the  sea. 

After  these  great  upheavals  the  crust  of  the  earth 
would  no  longer  be  fairly  even.  There  would  be  hills 
and  ridges,  with  corresponding  valleys  and  depres- 
sions. The  waters  would  settle  in  the  depressions, 
and  the  division  of  "dry"  land  and  water  would 
commence.  As  the  crust  becam.e  thicker  and  more 
irregular,  great  masses  of  it  might  be  undermined  by 
water,  far  below,  and  sink  or  "subside,"  making 
mighty  hollows  in  the  surface  of  the  earth.  Probably 
our  ocean-beds  were  formed  in  this  way.  It  drained 
the  shallow  seas  off  the  rest  of  the  crust,  and  made 
more  "dry"  land.  The  land,  in  other  words,  has 
been  gaining  on  the  water  all  through  the  history  of 
the  earth.  There  was  very  little  dry  land  at  first, 
and  there  were  no  mountains.  There  is  more  dry 
land  than  ever  to-day. 

This  may  seem  to  you  to  be  not  a  very  important 
matter  to  dwell  up  n,  when  I  have,  for  reasons  of 
space,  to  omit  thousands  of  interesting  features.    On 


28    LIFE  IN  THE  PRIMITIVE  OCEAN 

the  contrary,  it  is  most  important.  What  I  want 
especially  to  give  in  this  little  work  is  the  general 
machinery  of  evolution,  the  broad  principles  of  the 
subject.  And  this  constant  change  of  land  and  water 
is  a  most  important  part  of  the  machinery  of  the 
evolution  of  life.  You  might  poetically  imagine  it  as 
the  struggle  of  the  land  to  free  itself  from  the  water. 
In  the  course  of  time  it  has  thrown  the  bulk  of  the 
waters  into  deep  ocean  beds,  and  has  reared  itself  in 
high  mountain-chains  and  broad  continents.  The 
changes  which  this  restless  struggle  has  brought  about 
from  age  to  age  have  very  deeply  inlBuenced  the 
development  of  life,  as  we  shall  see. 

But  first  we  have  to  introduce  life  itself.  It  ap- 
peared at  a  very  remote  date  in  the  warm,  shallow 
ocean  of  the  primitive  earth.  How  long  ago  that  was 
we  cannot  say.  Most  geologists  would  say  between 
fifty  and  a  hundred  million  years  ago.  There  is, 
however,  a  new  school  which  professes  that  what  are 
called  the  "radio-active"  minerals  (minerals  whose 
atoms  break  up,  like  those  of  radium)  in  the  older 
rocks  show  that  the  earth  must  be  more  than  a 
thousand  million  years  old.  There  is  really  no  reason 
why  we  should  be  in  a  hurry  to  decide  how  old  the 
earth  is.  It  is  enough  that  the  story  of  life  on  it 
began  at  least  tens  of  millions  of  years  ago. 

Where  did  the  first  living  things  come  from,  and 
what  were  they  like?  That  is  a  mxOre  interesting 
question.     Unfortunately,  science  is  not  yet  able  to 


LIFE  IN  THE  PRIMITIVE  OCEAN    29 

give  a  confident  answer.  This  is  hardly  surprising. 
Man  is  at  least  half  a  million  years  old,  but  science 
is  only  about  two  centuries  old;  and  to  expect  it  to 
take  a  very  wonderful  and  complex  change  that 
occurred  a  hundred  million  years  ago  and  tell  us 
confidently  ' '  all  about  it "  is  to  expect  too  much.  We 
can  only  speculate,  and  there  are  two  chief  lines  of 
speculation. 

It  must  be  quite  understood  that  every  scientific 
authority  in  the  world  now  believes  that  life  was 
naturally  evolved  from  the  chemicals  of  the  early 
earth.  Everything  that  we  can  satisfactorily  study 
was  evolved.  We  have  therefore  a  right  to  assume 
that  all  things  were  evolved,  unless  such  a  natural 
evolution  is  in  any  particular  case  shown  to  be  impos- 
sible. No  one  has  ever  shown  that  the  natural  evolu- 
tion of  the  first  living  things  is  impossible,  or  even 
improbable,  so  we  take  it  for  granted.  That  is  per- 
fectly sound  logic  as  well  as  sound  science.  There 
is  one  distinguished  scientist,  Professor  Arrhenius, 
who  thinks  that  the  germs  of  life  came  to  us  from 
another  planet.  That  is  not  only  difficult  to  imagine, 
but  it  only  puts  the  problem  on  th  e  shelf  instead  of 
solving  it.  Life  was  naturally  born  in  the  shallow 
oceans  of  our  early  earth. 

There  are  many  theories  of  how  it  was  born,  and  I 
would  recommend  the  reader  who  wants  to  examine 
them  to  try  to  see  a  valuable  work  by  a  group  of 
American  professors,  called  The  Evolution  of  the  Earth 


30    LIFE  IN  THE  PRIMITIVE  OCEAN 

and  Its  Inhabitants  (191 8).  In  a  chapter  on  "The 
Origin  of  Life"  Professor  Woodruff  gives  all  the 
theories.  You  need  a  good  knowledge  of  chemistry  to 
understand  them  fully,  and  I  need  only  say  here  that 
both  chemists  and  biologists  agree  that  a  natural 
chemical  evolution  could  produce  the  first  living 
things.  But  you  must  be  careful  not  to  suppose  that 
even  the  lowest  living  things  in  nature  to-day — say, 
the  simplest  bacteria — were  directly  evolved  out  of 
inorganic  matter.  A  very  long  evolution,  with 
thousands  of  phases,  would  be  required.  It  would 
take  ages.  First  the  stuff  of  which  living  things  are 
made,  protoplasm,  would  have  to  be  formed  by  a  long 
series  of  chemical  changes  and  combinations.  Then 
this  stuff  would  have  to  break  up  into  the  distinct 
units  which  we  call  "cells";  for  each  of  the  simplest 
animals  and  plants  is  a  single  cell. 

When  I  spoke  of  "two  chief  lines  of  speculation," 
I  meant  that  you  may  suppose  that  the  natural 
development  of  life — what  used  to  be  called  "spon- 
taneous generation" — is  going  on  now  in  nature,  or 
that  it  only  occurred  under  the  very  special  conditions 
of  the  early  earth.  Both  these  views  are  held  by 
distinguished  biologists.  Professor  Benjamin  Moore 
has  an  excellent  little  work  on  the  former  line — that 
life  is  still  being  evolved  in  nature — in  the  "Home 
University  Library."  It  is  called  The  Origin  and 
Nature  of  Life  (1912).  He  and  other  eminent  au- 
thorities (such  as  Professor  Thomson,  of  Aberdeen) 


LIFE  IN  THE  PRIMITIVE  OCEAN    31 

believe  that  what  many  call  the  "mystery"  of  the 
origin  of  life  is  really  an  ordinary  event  in  nature's 
life  to-day.  It  would  be  below  the  level  of  the  micro- 
scope, so  that  the  old  controversy  about  "spon- 
taneous generation"  does  not  settle  the  question. 
Other  scientific  men,  perhaps  the  majority,  believe 
that  it  was  the  very  extraordinary  conditions  of  the 
early  earth  which  begot  life.  The  temperature  of  the 
ocean  was  very  high,  the  chemical  conditions  are 
unknown  to  us,  the  electrical  conditions  were  more 
pronounced  than  now,  and  there  may  have  been  a 
good  deal  of  radio-activity.  It  seems  more  probable 
that  the  evolution  of  life  was  due  to  these  special 
conditions,  which  have  passed  away  for  ever. 

It  is  hardly  necessary  to  point  out  that  much  the 
same  conditions  would  be  found  at  one  timiC  or  other 
on  all  the  planets  in  the  universe  of  any  size.  They 
are  globes  of  (generally)  the  same  m.aterial  as  ours, 
cooling  down.  That  is  why  we  expect  life  in  myriads 
of  other  places  besides  the  earth.  And  as  we  saw 
that  other  stars  are  older  than  ours,  and  some  have 
actually  run  their  course  and  died,  it  seems  likely 
that  the  full  story  of  life  had  been  played  out  on 
countless  globes  before  man  began  his  career  on  earth. 

Well,  we  return  to  the  first  living  inhabitants  of  the 
earth,  which  must  have  been  far  simpler  than  the 
lowest  bacteria  that  we  know.  In  fact,  it  would  be 
correct  to  say  that  there  were  no  "first "  living  things. 
Inorganic  matter  slowly  developed  into  organic,  and 


32    LIFE  IN  THE  PRIMITIVE  OCEAN 

this  was  slowly  shaped  into  living  units.  This 
particular  evolution  must  have  taken  ages.  There 
was  no  more  a  "first"  living  thing  than  there  was  a 
"first"  man.  Many  difficulties  will  be  avoided  if  we 
bear  in  mind  the  extremely  slow  and  gradual  nature 
of  these  evolutions. 

The  next  great  point  was  the  division  of  early  life 
into  plant  and  animal.  There  is  really  no  essential 
difference  between  the  two.  They  are  made  of,  sub- 
stantially, the  same  plasm,  and  in  the  lower  circles  of 
life  to-day  it  is  often  impossible  to  say  whether  a 
living  thing  is  a  plant  or  an  animal.  But  some  of 
the  early  inhabitants  continued  to  feed  on  inorganic 
matter — the  chemicals  in  the  soil — and  this  is  mainly 
what  we  mean  by  a  "plant"  of  vegetal  organism. 
As  the  soil  holds  the  chemicals  they  need  practically 
everywhere,  they  do  not,  as  a  rule,  require  locomotive 
organs.  They  "take  root."  And  as  sensitiveness  is 
of  no  use  to  stationary  beings,  they  do  not  develop 
sense  organs.  Thus  you  get  the  evolution  of  a  plant- 
world.  The  earliest,  of  course,  floated  in  the  water; 
but  some  took  root  in  the  soil  at  the  bottom  of  the 
ocean,  and  in  time  great  thickets  of  giant  sea-weeds 
arose.  We  will  trace  these  to  the  land  in  the  next 
chapter. 

Some  of  the  early  living  things  formed  the  habit  of 
devouring  their  neighbours,  instead  of  building  up 
plasm  out  of  inorganic  matter.  This  is  the  beginning 
of  the  animal.     It  is  quite  plain  that  this  means  a 


LIFE  IN  THE  PRIMITIVE  OCEAN    33 

precisely  opposite  development  from  that  of  the  plant. 
It  means  "hunting";  so  the  hunter  and  the  hunted 
develop,  very  gradually,  organs  of  locomotion,  sense- 
spots,  mouths,  stomachs,  weapons,  armour,  etc. 
Even  in  the  microscopic  life  of  the  pond,  where  every 
organism  is  still  a  single  cell,  you  get  bewildering 
variety  of  developments  of  this  kind.  But  we  cannot 
linger  here  over  this  stage. 

In  tim.e  the  cells  cling  together,  and  larger  animals 
("man^^-celled")  are  formed.  This  affords  a  better 
opportunity  for  specializing.  Some  cells  become 
muscle-cells,  some  nerve-cells,  some  stomach-cells, 
some  weapon-cells,  and  so  on.  You  can  see  all  this 
in  a  primitive  way,  under  the  microscope,  in  the 
common  pond  hydra.  The  jelly-fish  or  the  anemone 
you  find  at  the  coast  are  advances  of  the  same  type. 
The  animals  grow  larger  and  larger,  and  the  develop- 
ment of  their  separate  parts  increases.  Eyes  and 
other  senses  begin  as  little  pits  in  the  skin  lined  with 
sensitive  cells,  and  slowly  improve.  After  a  time  (in 
lowly  worms)  these  are  connected  with  each  other  and 
with  a  group  of  nerve-cells  in  the  head :  the  primitive 
brain. 

¥7hat  I  have  described  in  the  last  four  paragraphs 
certainly  took  millions  of  years,  and  probably  tens  of 
millions  of  years !  During  all  that  time  animals  were 
soft-bodied,  and  have  left  no  ''fossils."  It  is  by 
studying  them  in  nature  to-day  that  we  trace  the 
lines  of  their  evolution.     But  at  last  animals  with 


34    LIFE  IN  THE  PRIMITIVE  OCEAN 

hard  parts  were  developed,  and  we  begin  to  find  these 
preserved  as  fossils  in  the  rocks.  Some  began  to 
form  coats  of  lime  (shells),  and  the  great  family  of  the 
Molluscs  (mussels,  cockles,  oysters,  etc.)  spread  over 
the  floor  of  the  ocean.  Natural  selection  is  very 
useful  in  explaining  protective  parts  of  this  kind. 
Others  had  their  bodies  drawn  out  into  sections,  with 
a  tough  coat  on  each  section  (crabs,  water-fleas, 
shrimps,  etc.).  Others  had  long  wriggling  bodies 
(worms).  The  seas  now  teemed  with  life,  and  there 
was  a  mighty  struggle  for  food  and  safety.  The  less 
fit  perished,  age  by  age.  Organization  crept  higher 
and  higher. 

But  I  will  close  this  chapter  with  an  illustration  of 
the  way  in  which  the  geological  changes  which  w^ere 
going  on  all  the  time  influenced  the  living  things, 
even  in  the  water.  I  have  said  that  the  land  was 
rising  above  the  water,  as  the  ocean  sank  into  deeper 
beds.  We  have  strong  reason  to  think  that  these 
changes  were  often  acute  and  violent.  The  man  who 
says  that  the  secret  of  progress  is  "evolution,  not 
revolution,"  may  be  talking  very  good  social  philo- 
sophy— I  have  nothing  to  do  with  that — but  he  is  not 
talking  science,  as  he  thinks.  In  every  modem 
geological  work  you  read  of  periodical  "revolutions" 
in  the  story  of  the  earth,  and  these  were  the  great 
ages  of  progress — and,  I  ought  to  add,  of  colossal 
annihilation  of  the  less  fit. 

We  will  see  some  of  these  later.     Here  I  refer  to 


LIFE  IN  THE  PRIMITIVE  OCEAN    35 

one  which  occurred  at  the  period  we  have  reached. 
There  were  violent  changes  of  land  and  water.  Great 
continents,  which  had  for  ages  spread  out  very  fiat 
and  swampy,  were  tilted.  Mountain-chains  arose, 
with  mountain  torrents.  The  rivers,  which  had  been 
sluggish  for  ages,  became  far  swifter.  This  meant  a 
great  change  for  the  swimming  population.  Already 
the  hunt  for  food  and  escape  was  developing  swifter 
means  of  locomotion.  Now  the  water  itself  would 
wash  them  away  if  they  did  not  develop  more  power 
and  speed.  No  doubt  whole  vast  populations  of 
floating  and  swimming  things  perished,  and  the  speed 
of  others  was  more  rapidly  developed. 

At  the  close  of  these  great  changes  the  fish,  the 
king  of  the  early  ocean,  appears.  You  see  how 
beautifully  his  long  boat-like  body,  his  powerful  fins, 
his  eyes  and  nose  and  mouth  and  teeth  at  the  fore- 
end,  respond  to  the  new  conditions.  They  were  the 
outcome  of  a  very  long  and  hard  struggle.  And  the 
same  geological  changes  which  brought  about,  or 
hastened,  this  struggle  and  new  ''adaptation"  are 
now  going  to  open  a  new  and  most  important  chapter 
for  us. 


CHAPTER  IV 

LAND  LIFE   BEGINS 

More  than  half  the  story  of  life  was  over  at  the  time 
of  the  appearance  of  the  fish,  which  we  have  reached. 
That  half  of  the  story  is  not  only  very  imperfectly 
known  to  us,  but  it  is  difficult  for  people  who  have 
not  a  fair  knowledge  of  science  to  follow  it.  I  have 
therefore  dealt  with  it  on  very  broad  lines.  Those 
who  wish  to  know  more  may  consult  my  larger  work, 
Tht  Story  of  Evolution,  in  which  the  development  of 
each  branch  of  the  lower  animal  world  is  fairly  traced. 
The  second  half  of  the  story  of  life,  mainly  of  life  on 
land,  I  will  now  tell  more  in  detail.  It  is  easier  to 
follow,  and  it  will  illustrate  every  principle  of 
evolution. 

First,  then,  you  must  begin  by  thoroughly  grasping 
the  immense  influence  of  environment  on  the  evolu- 
tion of  living  things.  There  is  a  warm  controversy 
in  modem  science  as  to  the  respective  shares  of 
environment  (surroundings,  climate,  etc.)  and 
heredity.  If  you  read  some  of  our  English  writers, 
often  men  of  distinction  in  science,  you  will  get  the 
impression  that  it  is  old-fashioned  to  talk  about  the 
influence  of  environment;  that  all  changes  and  ad- 

36 


LAND  LIFE  BEGINS  37 

vances  are  caused  and  settled  in  the  germ-plasm  (the 
seed).  Do  not  believe  it.  The  science  of  heredity- 
is  still  very  obscure  and  imperfect,  so  I  am  saying 
little  about  the  internal  causes  of  those  changes  in 
animals  and  plants  which  make  evolution  possible. 
They  are  of  the  very  first  importance,  but  are  still 
obsciire.  What  is  clear  is  that  the  changes  in  the 
earth  itself  have  had  enormous  influence  in  directing 
these  variations  at  birth  into  the  formation  of  new 
species. 

Here  we  have  a  striking  illustration.  The  land 
rises,  the  rivers  flow  more  rapidly,  and  the  need  for 
speed,  which  was  already  great  on  account  of  the 
struggle  of  hunter  and  hunted,  becomes  greater  than 
ever.  The  fish  family  appears  in  the  waters,  begin- 
ning with  uncouth  forms  that  no  longer  exist,  passing 
on  to  the  shark,  then  branching  rapidly  into  hundreds 
of  types.  The  fins  were  probably  at  first  folds  of  the 
skin,  which  were  gradually  strengthened  by  ribs  of 
cartilage.  Bones  were  not  yet  developed.  The  lower 
fishes  of  to-day  (sharks,  rays,  etc.)  have  no  bones. 
They  are  the  survivors  of  one  of  the  earliest  families. 
The  backbone  is  the  chief  new  departure.  The  great 
"back-boned"  (vertebrate)  family  has  begun.  But 
the  backbone  was  at  first  not  a  bone  at  all.  It  was 
just  a  stiffening  rod  of  cartilage,  and  its  evolution  is 
easily  traced. 

We  must  turn  now  to  another  momentous  con- 
sequence of  the   geological  changes  which   I   have 


38  LAND  LIFE  BEGINS 

described.  It  is  useful  to  try  to  picture  this  early 
earth  on  which  a  new  act  of  the  drama  of  life  was 
opening.  There  was  little  solid  land.  A  warm  ocean 
rolled  over  the  greater  part  of  the  surface  of  the  globe, 
and  in  it  the  story  of  life  had  so  far  proceeded.  The 
atmosphere  was  foul  and  thick,  quite  unsuitable  for 
such  land  animals  as  we  know,  and  generally  saturated 
with  moisture.  The  enormous  quantities  of  carbon 
and  moisture  in  it  let  only  a  sombre  light  of  the  sun 
pierce  through;  but,  on  the  other  hand,  they  pre- 
vented the  heat  from  being  freely  reflected  back  into 
space,  and  an  almost  tropical  climate  existed  all  over 
the  earth.  There  was  no  winter  season.  Frost  and 
snow  were  unknown  anywhere. 

The  land  now  began  to  gain  on  the  water.  Ridges 
of  hill  no  doubt  arose,  but  most  of  the  new  "dry" 
land  would  be  broad  swamp  and  mud-flat.  Upon 
these  shores  life  began  to  crawl  from  the  overcrowded 
ocean.  Plants  must  have  led  the  way,  since  animals 
would  need  them  for  food.  We  know  that  the  con- 
ditions— steamy  swamps  and  an  atmosphere  rich  in 
carbon — were  good  for  such  types  of  vegetation  as 
there  were  at  the  time,  and  as  they  became  adapted 
to  land  life,  or  swamp  life,  the}^  throve  and  evolved. 
Low  types  of  ferns  and  mosses  appeared,  and  in  the 
rich,  warm,  low-lying  earth  they  found  a  golden  age. 
As  time  went  on  they  grew  to  gigantic  proportions. 
Most  of  them  are  now  extinct,  but  the  little  "mare's 
tail"  which  you  find  beside  a  stream  to-day  had  a 


LAND  LIFE  BEGINS  39 

cousin  among  the  early  plants.  It  grew  to  a  height 
of  forty  or  fifty  feet,  ordinarily,  and  sometimes  to 
nearly  a  hundred  feet !  It  was  an  age  of  giants.  Club 
mosses  ran  to  a  height  of  a  hundred  and  fifty  feet; 
and  even  tree  ferns  sometimes  spread  their  graceful 
dark  green  canopies  at  fifty  or  sixty  feet  above  the 
soil. 

The  animals  had  meantime  followed  the  vegetation. 
Their  skeletons  or  shells  are  now  buried  in  the  soil, 
which  has  become  our  rocks,  and  we  can  fairly  trace 
the  invasions  from  the  sea.  Snails  were  among  the 
earliest  arrivals.  Worms  of  various  kinds  became 
adapted  to  land  life.  Presently  we  find  traces  of 
insects — "primitive  bugs"  and  "primitive  cock- 
roaches," to  translate  the  learned  names  which  are 
given  to  them.  There  is  in  South  America  and  a  few 
other  places  to-day  a  very  primitive  little  creature, 
called  the  Peripatus,  which  you  would  take  to  be 
a  very  strange  caterpillar  if  you  met  it  in  the  wood. 
It  is  one  of  the  beings  of  the  remote  past,  which  has 
somehow  survived  the  struggle  of  ages,  and  it  helps 
us  to  understand  the  origin  of  the  insects.  Apparently 
some  of  the  worm-like  creatures  which  invaded  the 
land  from  the  sea  developed  tubes  in  the  skin  (a  sort 
of  tiny  "lungs")  for  breathing  air.  They  flourished, 
and,  as  is  almost  always  the  case  with  these  large 
prosperous  families,  they  scattered  and  evolved  in 
various  directions.  From  them,  we  think,  in  the 
course  of  time,  came  our  insects,  spiders,  scorpions. 


40  LAND  LIFE  BEGINS 

and  centipedes.  All  these  developed  gradually  in  the 
age  I  am  discussing. 

But  I  am  hurrying  over  these  lowly  creatures  in 
order  to  give  more  time  to  a  more  important  invader 
of  the  land.  This  was  the  fish.  You  may  think  it 
easy  enough  to  imagine  snails  and  worms  being 
adapted  to  life  on  land,  but  the  idea  of  a  branch  of 
the  fishes  leaving  the  water  and  becoming  land  ani- 
mals must  seem  strange  to  those  who  have  not  a 
good  knowledge  of  natural  history.  If  it  be  clearly 
understood  that,  as  I  have  so  often  said,  these  changes 
and  adaptations  to  a  new  life  were  very  slow  and 
gradual,  the  difficulty  lessens.  But  it  disappears 
altogether  when  you  take  a  good  work  on  natural 
history  and  zoology,  and  read  what  the  author  has  to 
say  about  "lung-fishes." 

He  will  tell  you  that  in  certain  rivers  of  Queensland 
there  are  short,  stumpy  fishes  which  have  a  lung  as 
well  as  gills.  The  water  of  those  rivers  runs  low  in 
the  summer,  and  the  lung  then  comes  into  play  to 
help  out  the  animal's  breathing.  You  v/ill  next  learn 
that  in  certain  rivers  of  Egypt  and  of  South  America 
there  are  fishes  of  the  same  family  with  two  lungs 
(like  ourselves)  as  well  as  gills.  The  rivers  in  which 
they  live  dry  up  entirely  in  the  summer.  The  gills 
(for  breathing  in  water)  are  then  useless.  The  fishes 
bury  themselves  in  the  dry  mud,  and  breathe  by 
their  lungs  until  the  waters  flow  once  more.  They 
can  walk  on  their  fins;  and,  in  fact,  the  fins  of  some 


LAND  LIFE  BEGINS  41 

of  them  are  more  like  slender  and  badly-made  limbs 
than  fins.  So  here  is  "a  fish  out  of  water"  that  is 
not  less  comfortable  than  in  water.  It  is  the  first 
amphibian;  a  connecting  link  between  life  in  water 
and  on  land. 

But  were  there  such  fishes  in  the  remote  age  which 
we  are  considering?  We  have  only  to  compare  the 
fossil  remains  of  certain  fishes  belonging  to  that  age 
with  the  skeletons  of  our  lung-fishes,  and  we  know 
that  there  were.  These  fishes  are  survivors  of  a  great 
family  of  lung-fishes  of  early  times;  and  as  we  find 
them  so  far  apart  as  Queensland,  Egypt,  and  Brazil, 
it  seems  that  this  family  must  at  one  time  have  been 
spread  over  the  entire  earth.  Some  branch  of  the 
family,  or  some  branch  of  the  fish-world  closely  re- 
lated to  them,  left  the  primitive  waters  and  began  the 
important  story  of  the  evolution  of  the  quadrupeds. 
We  are  not  quite  sure  from  which  branch  of  the 
ancient  fishes  the  quadrupeds  came.  If  it  was  not 
the  lung-fishes  themselves,  it  was  some  common 
ancestor  of  the  lung-fishes  and  another  group. 

Let  us  come  back  for  a  moment  to  the  gradual  rise 
of  the  land.  It  meant  that  enormous  shallow  seas 
which  had  become  densely  peopled  with  fishes  now 
disappeared.  It  meant  swifter  and  narrower  rivers. 
It  meant  less  lakes  and  lagoons.  It  meant  more 
circulation  of  the  moisture  in  the  atmosphere.  These 
are  the  things  to  study,  not  dreamy  speculations  such 
as  you  find  in  Professor  Bergson,  if  you  want  to 


42  LAND  LIFE  BEGINS 

understand  the  evolution  of  life.  The  decreasing 
lakes  and  rivers  and  shallow  seas  were  overcrowded. 
There  was  a  fearful  fight  for  oxygen  and  for  food. 
For  those  which  ventured  back  into  the  deep  seas 
there  were  sharks  thirty  feet  long,  with  teeth  five 
inches  long,  and  other  great  fishes  with  jaws  two  feet 
in  width,  waiting.  There  was,  in  a  sense,  a  race 
for  the  land — that  is  to  say,  an  increased  development 
of  adaptation  to  land  life.  Lungs  for  breathing  air 
were  the  chief  things  required ;  and  we  find  lungs  (or 
other  air-breathing  organs)  developing  on  all  sides. 
The  fish  would  develop  its  lungs  out  of  the  ''floating 
bladder,"  or  gas-bag,  which  it  already  had  for  swim- 
ming purposes.  In  some  fishes  this  bladder  is  double, 
and  is  already  connected  with  the  gullet  by  tubes. 

Naturally,  I  can  give  here  only  a  very  superficial 
account  of  what  happened,  but  all  the  details  of  the 
change  to  land  life  will  be  found  worked  out  in  larger 
scientific  works.  For  my  purpose  it  is  enough  to 
describe  how,  at  the  time  when  the  primitive  ferns 
and  mosses  spread  over  the  warm  earth  (in  what  a 
geologist  calls  the  "Devonian  Period,"  because  its 
most  characteristic  rocks  are  those  red  sandstone 
cliffs  you  may  have  seen  in  Devonshire),  a  great 
swarm  of  uncouth  lung-breathing  fishes  covered  the 
land.  No  doubt  they  "kept  one  leg  in  the  water/' 
so  to  say.  They  preferred  to  live  in  water  as  far  as 
they  could.  But  there  was  a  desperate  struggle  for 
food  in  the  crowded  waters,  while  the  land  had  as  yet 


LAND  LIFE  BEGINS  43 

no  other  large  animals  on  it,  and  was  becoming  rich 
in  insect  food.  As  these  lung-fishes  lived  more  and 
more  on  land,  walking  on  their  fins,  the  broad  paddle 
of  the  fin  was  slowly  converted  into  a  strong  and 
flexible  bony  stem — the  leg.  These  ancestral  quad- 
rupeds had  at  first  two  pairs  of  fins,  as  some  fishes 
have  to-day.  The  two  pairs  of  fins  gradually  became 
legs,  with  five  toes  (made  out  of  five  rays  of  the  fin) 
at  the  end.  The  lungs  continued  to  improve.  The 
amphibian — father  of  our  frogs  and  newts — made  his 
appearance.     The  quadruped  race  was  born. 

Let  us  glance  again  at  the  vegetation.  I  have  said 
that  there  was  no  cold  or  winter  anywhere  on  the 
earth.  We  know  this  because  the  fossil  plants  we 
find  are  all  of  a  semi-tropical  character.  As  there 
was  thus  no  winter  chill,  the  plants  throve  luxuriously, 
from  pole  to  pole,  all  the  year  round.  The  whole 
earth  was  semi-tropical  in  temperature,  and  most  of 
it  was  very  damp,  low-lying,  steamy.  This  suits 
ferns  and  mosses,  and  they,  as  I  said,  grew  to  gigantic 
sizes.  It  suited  them  also  that  the  air  was  rich  in 
carbon,  and  with  all  these  favourable  conditions  the 
plants  of  the  time  grew  denser  and  denser.  This 
period  of  "perpetual  summer  "  lasted  millions  of  years, 
and  we  are  not  surprised  to  learn  that  before  the  close 
of  it  the  earth  was  covered  with  such  forests  as  have 
never  been  seen  since. 

Here  another  interesting  question  has  been  answered 
by  the  story  of  evolution.     By  the  beginning  of  the 


44  LAND  LIFE  BEGINS 

nineteenth  century  it  was  well  known  that  there  were 
great  seams  of  coal  in  the  crust  of  the  earth,  and  it 
did  not  take  long  to  discover  that  these  seams  are  the 
decomposed  remains  of  extraordinary  forests  which 
at  one  time  covered  the  earth.  The  tree  trunks  and 
fern  leaves  are  often  quite  plain  in  the  coal.  But 
they  all  belonged  to  one  particular  and  remote  period 
(the  Carboniferous,  or  Coal-bearing,  period)  in  the 
story  of  the  earth.  Why  had  there  been  such  vast 
and  unique  forests  at  that  period?  I  have  given  the 
answer.  The  conditions  were  unique  for  that  kind 
of  vegetation.  It  was  the  golden  age  of  ferns  and 
mosses  and  similar  types.  It  has  given  us  the  coal 
seams  of  the  world. 

How  and  why  the  great  forests  came  to  an  end,  and 
have  never  re-appeared,  we  shall  see  in  the  next 
chapter.  Let  us  look  more  closely  at  them  before 
they  pass  away.  On- the  west  coast  of  New  Zealand 
I  have  looked  down,  from  the  summit  of  the  hills  a 
mile  or  two  inland,  upon  forests  of  tree  ferns  spread- 
ing above  a  great  carpet  of  every  variety  of  mosses. 
This  is  a  degenerate  patch  of  the  great  coal  forests 
of  long  ago.  It  has  no  longer  the  luxurious  conditions 
of  the  coal  forest.  The  winter  there  is  almost  as  cold 
as  in  London.  But  close  at  hand,  in  fact  often  under 
the  tree-fern  woods,  are  seams  of  coal  which  suggest 
that  these  great  stretches  of  fern  and  moss  have 
lingered  on  until  to-day ;  though  hardier  types  of  fern 
and  moss  have  taken  the  place  of  the  old  types. 


LAND  LIFE  BEGINS  45 

Trees  and  flowers  from  the  east  coast,  which  got 
them  from  the  warm  islands  beyond,  now  mingle 
with  the  fern  forests  of  New  Zealand ;  but  in  the  coal 
forest  there  were  no  flowers.  There  were  merely 
certain  crude  green  seed-organs,  that  we  might  call 
flowerets,  on  some  of  the  ferns;  and  in  a  later  chapter 
we  will  trace  the  evolution  of  the  flowers  from  these. 
There  was  a  monotonous  sombre  green  everywhere. 
No  birds  had  yet  appeared.  No  moths  or  butterflies, 
no  bees  or  wasps,  would  be  seen.  There  was  no  grass. 
Beetles,  fat  and  stumpy  spiders,  and  centipedes  were 
everywhere.  Great  flying  insects,  unlike  any  that 
we  know,  measuring  three  feet  across  the  wings,  were 
the  only  creatures  of  the  air.  Wings  began  to  be  im- 
portant, for  the  amphibious  creatures  that  were 
evolved  from  the  lung-fishes  swarmed  in  the  forests, 
and  grew  fat  on  the  rich  insect  world. 

We  have  innumerable  fossil  skeletons  of  these 
amphibians  of  the  coal  forests.  Our  frogs  and  toads 
were  not  yet  born,  but  creatures  of  the  newt  and 
salamander  type  ran  to  a  prodigious  size.  In  the 
swamps  was  a  giant  salamander,  about  five  feet  long, 
which  seems  to  have  been  the  monarch  of  creation  in 
those  days.  Almost  in  every  case  where  a  new  family 
appears  its  members  quickly  run  to  a  great  bulk  of 
body.  Food  is  very  abundant,  and  at  first  the  com- 
petition for  it  is  not  so  keen.  After  a  time  over- 
population begins  to  tell.  The  fat,  sluggish  types, 
which  had  had  no  work  to  do  but  eat,  are  very  much 


46  LAND  LIFE  BEGINS 

reduced.  Food  is  less,  and  it  must  be  hunted.  Can- 
nibalism is  apt  to  begin,  and  the  struggle  of  hunter 
and  hunted  brings  out  new  forms,  just  as  surely  as  a 
great  war  does. 

^  So  we  find  the  amphibia  of  the  coal  forests  branching 
out  in  many  directions.  Some  small  types  become 
tree  climbers,  and  no  doubt  they  found  a  rich  diet  of 
insects  in  the  trees.  This  reacted  on  the  insects,  and 
caused  fresh  developments  among  them.  Some,  as 
we  saw,  developed  wings,  and  could  at  least  soar  from 
tree  to  tree.  As  these  enjoyed  good  security,  for 
there  were  then  no  birds  or  flying  reptiles,  it  is 
natural  to  find  them  growing  to  a  large  size.  They 
had  fat,  heavy  bodies  eighteen  inches  long.  Other 
insects  were  fitted  for  survival  by  gradually  develop- 
ing such  a  shape  and  colour  that  they  could  not  be 
seen  at  any  distance.  These  were  the  "stick  insects " 
which  belong  to  the  ancient  order.  They  are  very 
common  in  Australia  to-day,  precisely  because  Aus- 
tralia and  New  Zealand  have  the  most  primitive 
animal  populations  on  the  globe. 

Other  amphibia  of  the  coal  forest  lost  the  use  of 
their  limbs,  and  developed  long  snake-like  bodies. 
These  give  us  an  excellent  clue  to  the  development  of 
the  later  serpent.  The  struggle  for  life  among  the 
amphibians  themselves  had  become  very  severe,  and 
some  had  taken  to  hiding  and  living  among  the  ex- 
posed roots  of  the  trees  by  the  side  of  the  swamps.  If 
you  have  ever  seen  a  picture  of  a  mango  forest  at  a 


LAND  LIFE  BEGINS  47 

river's  edge,  you  will  understand  this.  The  roots  form 
a  dense  thicket,  into  which  the  giant  salamander  or 
large  fish  could  not  follow  the  little  amphibian.  But 
legs  are  useless  in  such  a  world.  A  strong  wriggling 
body  is  needed;  and  the  fossil  skeletons  we  have 
show  us  that  this  branch  of  the  amphibians  slowly 
changed  until  they  must  have  looked  externally  like 
water  snakes. 

These  illustrations  of  the  machinery  of  evolution 
during  the  long  forest  period  will  suffice.  It  seems 
to  have  lasted  about  a  million  and  a  half  years;  or 
the  whole  period  we  have  just  surveyed  may  have 
lasted  ten  million  years.  In  spite  of  all  the  changes 
we  have  noticed,  it  was  a  period  of  slow  evolution. 
Life  is  never  quite  stagnant,  unless  some  race  of 
living  things  is  removed  entirely  from  competition 
with  others  and  has  easy  conditions.  I  mean  that 
for  a  living  family  of  low  intelligence,  which  depends 
on  almost  mechanical  stimulation  from  its  surround- 
ings, such  conditions  generally  mean  stagnation. 
They  are  rarely  found,  however,  and  we  saw  that 
there  was  a  brisk  struggle  in  the  coal  forests.  Yet, 
when  we  think  of  the  enormous  period  occupied 
by  these  developments,  the  pace  of  life  was  slow. 
Fat  salamanders,  fat  insects,  fat  spiders,  and  so  on, 
lived  out  the  warm  days  sluggishly  and  contentedly. 
Now  a  fearful  "revolution"  is  at  hand,  and  new 
dynasties  are  to  come  to  the  throne. 


CHAPTER  V 

IN  THE   GRIP  OF  AN   ICE  AGE 

We  have  already  begun  to  realize  what  a  deep  in- 
fluence changes  in  the  surroundings  may  have  on 
the  earth's  inhabitants,  although  I  have  been  able  to 
give  only  a  few  illustrations.  The  struggle  of  land 
and  water,  which  I  have  described,  caused  a  great 
number  of  other  new  developments.  Suppose,  for 
instance,  a  vast  marshy  region,  that  had  lain  stagnant 
for  hundreds  of  thousands  of  years,  were  tilted  and 
drained,  so  as  to  form  a  great  tract  of  dry  country 
with  a  few  swift-running  rivers.  The  whole  animal 
and  plant  population  must  change.  The  fish  and 
shell-fish,  the  luscious  plants  and  all  that  fed  on 
them,  down  to  the  microscopic  animalcules,  the  in- 
sects and  amphibians,  must  give  way  to  new  types. 
If  the  changes  are  very  gradual,  the  new  types  are 
largely  their  own  descendants.  There  is  time  for 
evolution  to  adapt  them  to  the  new  surroundings. 

This  was  happening  in  very  many  parts  of  the  earth 
during  the  period  we  have  just  considered;  and  we 
will  glance  at  one  further  effect  of  such  changes  before 
we  come  to  the  great  transformation  which  crowned 
them  all.     It  is  quite  plain  that  the  amphibious 

48 


IN  THE  GRIP  OF  AN  ICE  AGE       49 

animals  which  lived  in  one  of  the  regions  that  were 
being  gradually  drained  would  become  simply  land 
animals.  As  long  as  they  have  both  elements,  land 
and  water,  they  use  both.  But  even  in  nature  to-day 
we  have  frogs  that  live  in  trees  or  in  almost  waterless 
regions.  We  will  suppose  then  that,  as  the  waters 
are  drained,  these  large  primitive  salamanders,  as 
described  in  the  last  chapter,  take  m.ore  and  more  to 
the  land.  They  will  lose  their  gills.  Their  legs  will 
grow  stronger,  and  their  feet  firmer.  In  short,  the 
salamander  will  become  a  reptile  with  a  short,  stump}'' 
tail. 

This  new  branch  of  the  tree  of  life  appeared  before 
the  end  of  the  coal  forest  period.  The  reptile  was  the 
new  m^onarch  of  the  earth.  He  was  very  different 
from  the  snakes  and  lizards,  crocodiles  and  turtles, 
of  to-day.  He  had  a  thick,  squat  body,  several  feet 
long,  a  very  short  tail,  and  a  head  more  like  that  of 
a  frog.  He  was  the  patriarch  of  the  reptile  family, 
and  the  descendant  of  the  salamander  and  the  lung- 
fish.  But  he  appeared  for  the  same  reason  as  they 
did :  the  land  was  gaining  on  the  water. 

At  first  the  reptile  also  had  a  golden  age.  He  can 
live  in  water,  like  a  crocodile,  or  in  a  waterless  desert, 
like  some  of  the  Australian  lizards.  What  he  chiefly 
wants  is  warmth.  He  is  a  cold-blooded  animal.  That 
is  to  say,  his  heart  has  only  three  chambers,  so  that 
the  blood  purified  in  the  lungs  is  not  kept  completely 
separate  from  the  unpurified  blood,  and  it  does  not 


50       IN  THE  GRIP  OF  AN  ICE  AGE 

keep  a  constant  high  temperature.  In  cold  weather 
his  blood  grows  colder.  Also  he  lays  his  eggs — I 
mean  Mrs.  Reptile  lays  her  eggs — in  the  open,  and 
nature  must  supply  the  warmth  to  hatch  them.  In 
fine,  a  coat  of  scales  is  not  particularly  warm.  He 
loves  to  be  in  the  sun.  But  we  saw  that  he  appeared 
in  an  age  of  perpetual  semi-tropical  summer,  and  he 
prospered  and  multipHed  exceedingly. 

If  there  had  been  such  things  as  scientists  among 
those  early  reptiles,  the}^  would  have  made  a  strange 
and  disturbing  discovery.  Let  us  suppose  that  they 
had  records  of  the  preceding  ten  million  years.  The 
climate  would  be  recorded  as  "perpetual  summer," 
as  we  saw.  Surely  it  would  last  for  ever !  But  these 
reptile  scientists  would  presentl}^  make  an  unpleasant 
discovery.  The  earth  was  growing  colder.  If  they 
could  have  got  reports  from  all  parts  of  the  globe,  it 
would  have  been  the  same  story.  Century  by  century 
the  earth  was  growing  steadily  colder.  In  many 
places  the  land  was  rising,  slowly,  to  unknown 
heights.  Whole  regions  had  to  be  deserted.  The 
warm-loving  vegetation  of  the  tim^e  could  not  live 
in  them.  There  was  no  food.  The  other  regions 
became  over-populated.  There  was  the  usual  fierce 
struggle  and  active  evolution.  The  hardier  specimens 
had  a  better  chance.  They  could  live  where  most  of 
the  others  could  not.  Some  of  them  became  gradually 
adapted  to  a  cold  climate. 

To  drop  this  little  parable,  and  state  the  facts  in  a 


IN  THE  GRIP  OF  AN  ICE  AGE       51 

word:  the  long  perpetual  summer  of  the  early  earth 
ended  in  a  great  Ice  Age.  That  is  to  say,  about  four 
million  square  miles  of  the  earth's  surface  were 
covered  with  a  permanent  sheet  of  snow  and  ice,  as 
our  Arctic  and  Alpine  regions  are  to-day.  We  can 
detect  traces  of  glaciers,  or  rivers  of  ice,  millions  of 
years  after  they  have  disappeared.  Their  weight  is 
such  that  they  grind  pebbles  deep  into  granite  rocks, 
and  the  scratches  remain  almost  for  ever,  in  suitable 
places.  There  had  been  two  earlier  Ice  Ages  in  the 
story  of  the  earth;  but,  as  we  saw,  there  was  then  no 
life  on  land,  and  we  have  not  considered  them.  This 
new  ice  sheet  stretched  from  India  to  Australia  and 
Africa.  A  great  continent  spread  over  that  area  at 
the  time,  and  it  must  have  been  one  vast  Arctic 
region.  I  have  seen  the  marks  of  glaciers  of,  say, 
nine  or  ten  million  years  ago — the  periods  we  have 
reached — in  Australia. 

Four  million  square  miles  are  by  no  means  the 
entire  land  surface  of  the  earth,  but  the  climate  of  the 
whole  earth  seems  to  have  changed.  No  doubt  there 
were  smaller  sheets  of  ice  in  other  regions.  Wherever 
there  were  mountains  there  would  be  at  least  a  frozen 
winter-time.  And  there  were  now,  for  the  first  time 
in  millions  of  years,  many  mountains.  That  is,  in 
fact,  probably  the  great  cause  of  the  Ice  Age.  I  have 
carefully  studied  Ice  Ages  in  my  Story  of  Evolution 
and  End  of  the  World,  and  am  convinced  that,  as 
many  geologists  think,  the  cause  of  Ice  Ages  is  a  great 


52       IN  THE  GRIP  OF  AN  ICE  AGE 

elevation  of  the  land.  We  saw  that  during  the  pre- 
ceding period  the  earth  was  generally  low-lying  and 
steamy.  A  very  thick  atmosphere  brooded  over  it, 
and,  like  the  panes  of  glass  of  a  hot-house,  it  kept  the 
heat  down  at  the  earth's  surface.  This  thickness  of 
the  atmosphere  was  partly  due  to  the  enormous 
masses  of  carbon  (in  the  shape  of  carbonic  acid  gas, 
or  carbon  dioxide)  in  it.  The  great  forests,  which 
absorb  carbon  and  give  out  oxygen,  had  altered  this. 
But  the  dense  moisture  of  the  early  atmosphere  had 
the  same  effect.  The  great  rise  of  land  now  altered 
the  moisture.  It  swept  up  the  cooler  hill-sides  and 
was  turned  into  rain,  or  "precipitated."  There  was 
more  running  water,  and  less  brooding  moisture  and 
stagnant  water.  This  purification  of  the  atmosphere, 
combined  with  the  rise  of  mountain  chains  high  up 
above  the  sea  level,  is  enough  to  explain  an  Ice  Age. 

The  change  may  have  taken  a  hundred  thousand 
years.  Indeed,  it  was  really  the  last  stage  of  a  change, 
the  struggle  of  land  and  water,  that  we  have  traced 
for  some  time.  There  was  no  evident  upheaval. 
What  geologists  mean  when  they  call  it  a  revolution 
— this  period  they  call  "the  Permian  Revolution" — 
is  that  the  story  of  the  evolution  of  life,  taken  as  a 
whole,  shows  at  this  point  a  more  rapid  and  funda- 
mental change. 

It  is  quite  easy  to  see  that  the  change  of  climate 
would  certainly  mean  a  revolution  for  animal  and 
plant  life.     You  m-ay  bring  a  negro  chief  from  Africa 


IN  THE  GRIP  OF  AN  ICE  AGE       53 

to  Norway  without  much  risk  to-day,  because  you  can 
give  him  Jaeger  vests,  a  tweed  suit,  and  a  fur  coat. 
But,  if  clothing  were  unknown,  what  would  be  the 
effect  of  transporting  a  party  of  Zulus  to  Northern 
Siberia?  Well,  as  we  saw,  practically  the  whole  of 
the  earth's  inhabitants  had  been  living  in  an  African 
climate,  and  the  worst  kind  of  moist  African  climate, 
for  millions  of  years.  No  doubt  there  were  some 
drier  regions,  as  the  land  rose;  but  the  fossil  remains 
show  that  they  were  few.  Nearly  all  the  plants  and 
animals  of  the  time  were  suited  only  to  a  moist,  hot 
climate,  and  were  too  sluggish  to  be  re-adapted. 

As  a  natural  result,  there  was  a  prodigious  carnage 
of  the  living  inhabitants  of  the  earth.  This  is  the 
worst  aspect  of  "natural  selection."  It  is  a  fearfully 
effective  method,  but  slow  and  costly  and  ruthless. 
We  should  say  that  it  is  a  cruel  and  stupid  method, 
only  nature  is  not  intelligent  and  responsible.  People 
who  call  it  a  *'law  of  nature,"  and  so  say  that  we  must 
follow  it  to-day,  are  rather  confused.  It  was  a  law  of 
nature.  That  is  all  that  science  can  say.  However, 
we  will  return  to  this  point  later. 

It  has  been  calculated,  from  the  fossil  remains  of 
the  period  before  and  after  the  Ice  Age,  that  thirty- 
nine  out  of  forty  of  all  the  species  of  animals  and 
plants  on  the  earth  during  the  coal  forest  age  were 
destroyed.  They  disappear  from  the  calendar  alto- 
gether. The  luscious  vegetation  withered  away.  The 
dense  forests  died,  and  their  remains  were  packed 


54       IN  THE  GRIP  OF  AN  ICE  AGE 

underground,  to  become  the  coal  seams  of  man's  early 
industrial  age.  Nearly  every  type  of  the  old  vegeta- 
tion was  blotted  out.  We  can  trace  some  of  the  ferns 
and  other  trees  gradually  becoming  hardier.  We 
find  pines  and  yews  and  firs,  or  their  ancestors,  now 
for  the  first  time  appearing  on  the  earth.  But  it 
was  a  very  thin  diet  they  provided  compared  with 
what  had  gone  before,  and  the  fat  salamanders  and 
insects  and  other  large-feeding,  sluggish  animals  went 
the  way  of  all  flesh.  Only  a  few  types  were  pre- 
served in  warmer  regions,  to  give  us  the  amphi- 
bians, stick  insects,  beetles,  spiders,  etc.,  of  the  new 
age. 

It  was  a  great  annihilation.  Up  to  that  time  in  the 
story  of  the  earth  motherhood  consisted  merely  in 
shedding  eggs  on  the  surface  of  the  earth  or  in  its 
waters.  To  put  it  poetically,  * '  nature ' '  mothered  the 
eggs.  The  warm  ground  or  water  gave  heat  enough 
to  stimulate  the  wonderful  mechanism  in  the  eggs. 
In  the  colder  age  we  are  considering  there  would  not 
be  heat  enough.  Even  if  the  mother  got  sufficient 
food  to  reach  the  egg-laying  stage,  the  old  habit  of 
entrusting  the  eggs  to  nature  was  out  of  date;  ex- 
cept, as  I  said,  in  favoured  localities  which  kept  the 
old  conditions  more  or  less,  and  must  have  been 
greatly  overcrowded.  A  new  habit,  the  practice  of 
caring  for  one's  eggs  or  young,  was  needed  in  a  cold 
climate. 

Then  there  was  the  direct  effect  of  the  cold.     The 


IN  THE  GRIP  OF  AN  ICE  AGE       55 

reptiles  would  have,  at  first,  thin  scaley  coats  of  little 
use.  The  amphibians  had  the  clammy  skins  of  our 
frogs  and  newts.  None  of  the  animals  had  had 
occasion  to  develop  warm  coats.  None  of  them  had 
hearts  so  constructed  as  to  keep  the  blood  at  an  even 
temperature.  However,  the  climate  changed.  I  have 
walked  on  the  brink  of  Niagara  and  by  the  lake  side 
at  Chicago  in  just  the  same  clothing  as  I  wear  in 
the  early  summer  in  London,  without  any  particular 
discomfort.  The  mammal  has  a  four-chambered 
heart,  and  the  blood  is  so  well  supplied  with  oxygen 
to  burn  its  "fuel"  that  it  keeps  warm.  None  of  the 
animals  before  the  Permian  Revolution  had  "warm 
blood."  There  had  been  no  need  of  it,  and  needless 
things  are  not  evolved.  If  some  theories  of  evolution 
were  true,  they  might  be.  On  the  lines  of  natural 
selection  they  are  not. 

But  on  the  theory  of  natural  selection  they  are 
evolved  when  they  are  needed,  and  this  is  the  positive 
or  constructive  side  of  the  matter.  We  have  seen 
that  the  three  great  new  requirements  in  the  higher 
animals  were  care  of  the  eggs  or  young,  a  four- 
chambered  heart,  and  a  warm  coat.  You  probably 
know  that  these  are  the  chief  points  in  which  the 
mammals  and  birds  are  superior  to  the  reptiles.  You 
will  understand  half  of  familiar  nature  better  in  future 
if  you  remember  that  these  superior  qualities  were 
made  necessary  by  a  great  Ice  Age,  nine  or  ten  million 
years  ago,  and  were  evolved  in  the  latter  part  of  the 


56       IN  THE  GRIP  OF  AN  ICE  AGE 

Ice  Age.  The  bird  and  the  mammal  are  products  of 
an  Ice  Age. 

We  will  try  to  picture  what  happened.  The  ice 
sheet  spread  over  South  Africa  and  the  continent 
which  then  spread  from  Africa  to  Australia  in  the 
east  and  India  in  the  north-east.  Suppose  we  take 
the  northern  part  of  Africa,  which  was  free  from  ice. 
Our  African  tropics  would  then  be  a  "temperate 
zone."  Further  north  there  would  still,  no  doubt, 
be  large  regions  with  warm  conditions.  But  the 
overcrowding  would  be  terrible.  How  many  million 
' '  refugees ' '  would  there  be  from  the  icy  continent  ?  I 
do  not,  of  course,  mean  refugees  in  the  modern  sense. 
The  change  had  taken  ages.  The  animals  would 
migrate  gradually.  But  in  the  height  of  the  Ice  Age 
the  warm  region  would  be  packed. 

On  the  fringes  of  such  a  region  natural  selection 
would  be  at  work.  If  you  take  a  thousand  people  at 
random  in  London,  you  find  that  some  stand  cold 
better  than  others.  There  are  little  variations  of  all 
kinds  in  every  species.  Now  the  power  to  stand 
cold  would  be  an  advantage  in  the  conditions  we  are 
studying.  Such  individuals  would  be  more  active,  and 
could  get  food  enough  in  regions  where  others  would 
starve.  These  would  prosper  in  the ' '  temperate  zone, ' ' 
which  would  not  be  so  densely  inhabited.  The  more 
tender  and  sluggish  among  their  offspring  would 
perish.  The  hardier  and  more  active  would  multiply. 
The  standard  of  the  population  would  rise.    As  they 


IN  THE  GRIP  OF  AN  ICE  AGE        57 

increased,  and  the  struggle  for  life  increased,  the 
hardier  and  more  active  would  tend  always  to  push 
into  the  more  temperate  parts.  Any  useful  variation, 
such  as  the  overlapping  of  the  scales  or  an  improve- 
ment of  the  blood  circulation,  would  be  fostered  by 
natural  selection.  Just  as  lungs  were  the  great  thing 
needed  at  the  earlier  stage,  so  warmth — for  the  parent 
and  eggs — is  now  the  chief  need.  The  machinery  of 
natural  selection  worked,  age  after  age,  in  develop- 
ing heating-apparatus.  The  bird  was  one  result;  the 
mammal  was  another. 

If  we  could  accept  the  theory  called  "  Mendelism," 
which  I  have  mentioned  in  the  first  chapter,  this 
would  in  one  sense  be  easier  to  understand.  Ac- 
cording to  this  theory,  evolution  does  not  work  by 
very  slowly  and  gradually  adding  together  little 
changes  in  successive  generations,  but  by  occasionally 
producing  young  that  differ  very  materially  from  the 
mother.  Such  things  are  known,  and  used  to  be 
called  "freaks."  Many  scientists  believe  that  they 
are  sometimes  the  beginning  of  new  species.  If  we 
could  imagine  a  mother  with  a  three-chambered  heart 
(a  cold-blooded  mother)  laying  an  egg  which  hatched 
into  a  reptile  with  a  four-chambered  heart  (a  warm- 
blooded animal),  or  a  long  step  towards  it,  evolution 
would  be  easier.  But  it  is  a  large  order,  and  the 
supposition  does  not  seem  to  be  justified  by  the  facts. 
Most  men  of  science  still  believe  in  gradual  advances; 
though  they  lay  far  more  stress  than  Darwin  did  on 


58       IN  THE  GRIP  OF  AN  ICE  AGE 

the  embryonic  machinery  which  must  be  the  cause  of 
all  advances.  Surroundings  only  select  the  variations 
which  are  provided  by  the  embryonic  machinery. 

These,  however,  are  deeper  matters  than  we  can 
discuss  here.  The  Ice  Age  may  have  lasted  a  quarter 
of  a  million  years.  It  put  the  population  of  the  earth 
through  a  sieve,  as  it  were.  The  great  majority  of 
the  plants  and  animals  could  not  stand  the  test,  and 
they  were  rejected.  A  few  types  struggled  through, 
and  they  begin  the  story  of  higher  animal  life:  the 
life  of  the  birds  and  the  mammals.  But  this  figure  of 
speech  is  very  faulty  in  one  sense.  If  the  severe 
conditions  of  life  had  been  spread  all  over  the  earth, 
it  would  be  a  good  figure.  But  they  were  not,  as  we 
saw.  There  were  still  warm  regions,  where  modified 
survivors  of  the  old  Golden  Age  huddled  together.  If 
the  old  warm  conditions  returned  to  the  earth,  they 
would  spread  over  it  once  more.  This  is  what 
happened.  The  ice-sheet  gradually  melted  away, 
probably  because  the  land  gradually  sank  once  more, 
and  a  new  and  curious  chapter  of  the  story  of  life 
opened. 


CHAPTER  VI 

THE  BRONTOSAUR  AND  ITS  COUSINS 

The  entire  period  we  have  covered  so  far  is  called 
by  geologists  the  ''Ancient  Age"  of  the  earth.  It 
embraces  more  than  two-thirds  of  the  life  of  the 
earth.  If  you  want  to  know  the  correct  scientific 
names,  there  was  first  a  very  long  period,  probably 
as  long  as  all  the  others  put  together,  called  the 
Archcsan  Era,  which  we  may  call  the  Very  Ancient 
or  Primordial  Era.  If  you  take,  for  convenience,  the 
age  of  the  earth  as  100,000,000  years,  this  part  lasted 
50,000,000  years.  There  was  life  only  in  the  later 
part  of  it,  and  no  life  on  land.  Then  there  was  a 
long  period  of  35,000,000  years  (on  the  same  scale) 
which  geologists  call  the  Primary  or  Palaeozoic 
(Ancient  Life)  Era.  That  is  the  period  we  have 
covered  in  the  last  three  chapters.  In  this  chapter 
we  are  going  to  survey  the  "Middle  Ages"  (the 
Secondary  or  Mesozoic  Era)  of  the  earth's  story. 

And  some  very  quaint  mediaeval  creatures  there 
were  in  it,  you  will  say !  It  was  the  age  of  the  giant 
reptiles,  whose  hundred-foot-long  skeletons  you  see 
in  museums  or  works  of  science.  It  was  the  age 
of  the  Brontosaur,  v»rhich  was  photographed  and  de- 

59 


60  THE  BRONTOSAUR  AND  ITS  COUSINS 

scribed  in  all  our  newspapers  a  year  ago.  I  am,  as 
usual,  not  so  much  going  to  describe  these  things  as 
to  explain  them. 

We  saw  that  reptiles  had  been  developed  from 
amphibians  in  the  latter  part  of  the  coal  forest  age. 
They  were  a  plain  response  to  the  change  of  con- 
ditions. Dry  land  was  increasing.  The  salamander 
took  to  dry  land,  and  became  a  reptile.  But  the  dry 
land  increased  so  much,  and  rose  so  high,  that  it 
threatened  to  strangle  the  new  monarch  of  the  earth 
very  speedily.  Fortunately  for  him,  there  were  still 
warm  regions,  and  there  he  awaited  his  turn.  I  im- 
agined a  group  of  reptile  scientists  keeping  accounts. 
For  a  hundred  thousand  years  or  more  they  would 
report  increasing  cold,  and  dire  would  be  the  pro- 
phecies. Then  for  a  hundred  thousand  years  or  more 
they  would  report  decreasing  cold,  and  hope  would 
animate  the  chilly  reptile  breast.  Never  believe 
prophets  who  venture  more  than  forty-eight  hours 
ahead.  (In  the  end  of  this  work  I  will  venture  ten 
million  years  ahead — but  that  is  different.) 

The  sun  shone  again  upon  the  whole  world.  The 
new  age  was  not  as  hot  as  the  previous  one,  for  the 
atmosphere  was  now  purified  of  its  great  masses  of 
carbon  and  moisture.  But  it  was  again  perpetual 
summer  all  over  the  earth ;  no  cold  or  frost  or  winter 
anywhere.  It  was  more  brilliant  sunshine  than  be- 
fore. Sombre  trees  like  the  yews  and  firs  remained  in 
temperate  regions,  but  the  new  types  of  trees — very 


THE  BRONTOSAUR  AND  ITS  COUSINS  6i 

largely  the  palm-like  trees  called  "cycads" — spread 
luxuriantly,  as  the  cold  retreated  from  level  to  level. 
Large  yellow  flowers,  the  first  touch  of  colour  (except 
dark  green)  the  earth  had  yet  known,  responded  to 
the  bright  sun.  These  I  will  reserve  for  a  later  chap- 
ter, and  the  reader  must  go  to  larger  books  for  the 
names  and  pictures  of  the  new  plants.  It  is  enough 
here  to  say  that  in  the  new  Golden  Age  the  vegetation 
wove  once  more  a  thick  mantle  over  the  earth,  and 
food  became  again  enormously  abundant. 

The  height  of  the  land  explained  the  cold.  The 
lowness  of  it  now  explains  the  warmth.  It  was  as  if, 
in  our  great  struggle  of  land  and  water,  the  land, 
which  seemed  to  triumph  in  the  Permian  Revolution, 
was  again  worsted  for  a  time.  This  may  remind  you 
of  the  French  Revolution,  and  it  is  a  very  good 
parallel  to  remember.  The  sluggish  old  types  of 
monarchs  were  dethroned  at  the  Permian  Revolution, 
with  great  bloodshed,  and  progressive  new  rulers  of 
the  earth  were  introduced  (the  bird  and  the  mammal). 
But  there  was  a  great  reaction,  and  the  sluggish  old 
monarchs  cam^e  back.  The  reptiles  are  now  to  lord 
the  earth  for  a  few  million  years.  The  bird  and 
mammal  will  slink  into  such  obscurity  that  we  need 
not  notice  them.  To  complete  the  parallel,  we  shall 
see  that  this  reaction  will  be  shattered  by  a  new 
revolution  (which  we  may  compare  to  the  revolution- 
ary movement  of  1830-2),  then  there  will  be  a  moder- 
ate reaction,   and  finally  another  great  revolution 


62  THE  BRONTOSAUR  AND  ITS  COUSINS 

(which  we  may  compare  to  the  period  1848-70).  It 
is  said  that  there  will  be  another  Ice  Age  some  day ! 

To  return  to  our  Middle  Ages  and  Brontosaurs. 
The  earth  was  again  generally  low-lying,  but  sunny 
and  with  a  clearer  air.  Europe  was  mostly  under 
water.  Only  the  summits  of  its  higher  hills  peeped 
above  water,  apart  from  a  few  regions  which  are  now 
elevated  table-lands.  Europe  was,  in  fact,  mainly  an 
archipelago,  like  the  Pacific  Islands.  A  warm  blue 
ocean,  with  prodigious  sharks  and  swimming  reptiles, 
covered  the  greater  part.  Coral  reefs  of  great  beauty 
fringed  the  islands;  we  find  their  remains  now  high 
up  on  our  mountains.  There  was  more  land  where 
the  North  Atlantic  now  is  than  in  Eurpoe.  A  swampy 
continent  stretched  from  Scotland  to  America,  and  the 
great  animals  wandered  (as  species)  from  continent 
to  continent. 

These  conditions  explain  the  Brontosaur  and  its 
cousins.  Probably  most  of  the  larger  reptiles  were 
swamp  animals,  floating  their  great  bulk  on  the 
water  like  the  hippopotamus.  If  you  notice  carefully 
the  very  small  allowance  of  leg  to  the  monstrous 
skeleton  of  the  Diplodocus  in  the  South  Kensington 
Museum,  and  the  breadth  of  foot,  you  will  realize 
this.  One  can  hardly  imagine  it  walking,  much  less 
running !  Probably  most  of  these  larger  "  Deinosaurs," 
as  this  group  of  the  reptiles  is  called,  were  aquatic 
animals.  Food  was  very  abundant,  and  they  were 
vegetarians,  taking  in,  lazily,  tons  per  day  of  the 


THE  BRONTOSAUR  AND  ITS  COUSINS  63 

luscious  vegetation  that  abounded.  The  Brontosaur 
was  quite  a  modest  member  of  the  family.  He 
weighed  only  about  twenty  tons  when  he  was  fully 
grown!  But  as  his  length  was  only  sixty  feet,  the 
Diplodocus  (eighty  feet)  must  have  been  much 
heavier;  and  we  now  know,  from  bones  we  have 
found  in  America,  that  some  of  these  Deinosaurs 
were  about  twice  as  long  as  the  Diplodocus,  or  a 
hundred  and  sixty  feet  long. 

Another  branch  of  the  family  were  leaping  reptiles. 
Some  stood  only  about  two  feet  high,  when  they  were 
erect,  and  others  thirty  or  forty  feet.  There  were 
some  with  hollow  bones,  like  birds,  so  that  we  must 
not  allow  the  lazy  monsters  of  the  swamp  to  mislead 
us.  The  new  ''Golden  Age"  was  not  long  an  age  of 
tranquillity  and  mere  feeding.  The  inevitable  struggle 
for  life  began.  At  all  periods  in  the  history  of  the 
earth  part  of  a  family  has  been  apt  to  turn  carnivorous 
and  prey  upon  its  fellows,  and  the  skeletons  and  teeth 
of  the  great  reptiles  show  that  this  terrible  struggle 
set  in  in  the  Mesozoic  Age.  Teeth  grow  larger  and 
more  numerous  and  more  carnivorous,  until  at  last 
we  get  appalling  fiesh-eating  monsters  with  two  or 
three  hundred  formidable  teeth  in  their  jaws. 

Armour,  as  is  usual,  keeps  pace  with  the  develop- 
ment of  teeth.  Ponderous  and  sluggish  vegetarians, 
forty  feet  long,  developed  rows  of  great  plates  of  bone 
standing  upward  from  their  backbones.  Others  had 
massive  coats  of  horn  over  their  heads  and  necks, 


64  THE  BRONTOSAUR  AND  ITS  COUSINS 

running  to  sharp  points  in  front.  Towards  the 
close  of  the  period  we  find  perfectly  weird  de- 
velopments of  jaws,  teeth,  and  armour.  Professor 
Huxley  was  quite  right  in  saying  that  "Nature, 
red  in  tooth  and  claw,"  had  been  the  great  agency 
in  evolution.  It  is  only  at  a  much  later  stage 
that  we  shall  find  the  gentler  influence  of  social 
life  becoming  a  factor  of  any  consequence  in  de- 
velopment. 

The  struggle  of  vegetarian  and  carnivore  explains 
much  more  than  the  development  of  arms  and 
armour.  If  you  go  into  the  fossil  reptile  gallery  of 
a  great  geological  museum,  you  are  amazed  at  the 
variety  of  types  which  grew  out  of  the  primitive 
simple  family.  In  the  centre  of  the  gallery  you  will 
find  the  monstrous  thigh  bones,  and  perhaps  whole 
skeletons,  of  the  vast  Deinosaurs,  which  lazed  in  the 
swamps.  Near  them  are  mounted  skeletons,  standing 
up  twenty  or  thirty  feet,  of  reptiles  whose  long  and 
powerful  back  legs  make  them  look  like  kangaroos. 
They  were  the  leapers.  On  the  walls  are  the  fossil 
remains  of  others  which  lived  entirely  in  the  sea; 
some  with  fish-like  bodies  and  well-developed  paddles, 
some  with  long  necks  that  could  reach  to  the  bottom 
in  search  of  food,  some  with  eyes  fifteen  inches  in 
diameter  or  jaws  like  crocodiles.  In  other  cases  are 
the  skeletons  of  flying  reptiles,  from  small  creatures 
about  the  size  of  a  wild  goose  to  villainous-looking 
"dragons"  with  a  stretch  of  twenty  feet  across  the 


THE  BRONTOSAUR  AND  ITS  COUSINS  65 

expanded  wings  and  jaws  that  would  bite  a  square 
foot  of  flesh  out  of  an  elephant. 

This  variety  is  an  expression  of  the  struggle  for 
life.  Every  little  advantage  for  escape  was  favoured 
and  strengthened  during  hundreds  of  thousands  of 
years  of  conflict,  and  the  branches  of  the  family 
spread  in  all  directions.  Some  went  down  into  the 
sea,  where  great  sharks  v/ere  their  only  competitors. 
Some  developed  powerful  back  legs,  and  could  outpace 
even  a  running  carnivore.  They  were  often  far  larger 
than  the  giant  kangaroo,  and  must  have  been  able  to 
do  a  remarkable  "long  jump."  Some  climbed  trees, 
and  it  is  probably  from  these  relatively  small  and 
active  creatures  that  the  flying  reptiles  were  evolved. 
Some  think  that  flying  began  with  running,  but  it 
seems  more  likely  that  its  origin  was  in  leaping  down 
from  low  branches  of  trees  when  a  pursuer  mounted 
the  tree.  Webby  fore-feet  would  be  an  advantage. 
The  animal  could,  in  our  aeronautical  language,  glide 
or  plane  down  to  the  ground;  and  a  long  course  of 
this  evolution  of  "webbiness"  would  at  last  give  a 
powerful  membrane  from  the  first  toe  (which  grew  to 
a  length  of  several  feet)  to  the  side  of  the  body — the 
plane  or  wing  of  the  flying  reptile. 

As  far  as  general  principles  are  concerned,  therefore, 
we  very  fairly  understand  the  wonderful  family  of 
reptiles — some  writers  strangely  persist  in  calling 
them  "lizards" — which  filled  the  land,  the  waters, 
and  the  air  of  the  earth's  Middle  Ages.  There  are  a 
5 


66  THE  BRONTOSAUR  AND  ITS  COUSINS 

great  many  controversies  about  the  origin  and  rela- 
tions of  different  tj^pes,  but  these  things  cannot  be 
discussed  here.  It  is  only  necessary  to  add  that  the 
remainder  of  the  animal  world  continued  to  make  the 
sam^e  progress,  though  while  these  monstrous  and 
curious  brutes  occupy  the  Mesozoic  stage  the  others 
have  little  interest. 

The  bird  and  the  mammal  were  there,  in  very 
primitive  forms,  all  the  time;  but  the  reptiles,  if  they 
had  had  the  power  to  reflect,  would  have  considered 
them  very  insignificant.  They  were  so  small  and 
furry,  or  feathery,  that  they  were  not  even  good  food. 
A  reptile  philosopher  would  have  regarded  them  as 
freaks  of  the  family.  He  might  have  said  that  they 
were  what  we  now  call  "anachronisms";  that  is  to 
say,  things  that  had  had  a  sensible  meaning  at  one 
time  or  other,  but  ought  to  have  died  out  in  the  age 
to  which  they  really  belonged — the  Ice  Age.  What 
use  were  fur  and  feathers,  four-chambered  hearts,  and 
making  a  fuss  over  one's  eggs  or  young,  in  a  gloriously 
warm  age  like  the  Mesozoic?  Their  one  advantage 
was  brain,  for  better  blood  meant  a  better-nourished 
brain.  But  their  advantage  in  this  respect  was  not 
overpowering — they  had  less  brain  than  a  rabbit  or  a 
goose — and,  in  any  case,  brain  was  not  much  regarded 
in  that  age  of  brawn.  A  twenty-ton  reptile  like  the 
Brontosaur  had  a  brain  no  larger  than  a  man's  fist. 

So  we  leave  the  mammals  and  birds  for  later 
chapters.     The  amphibians  naturally  throve  like  the 


THE  BRONTOSAUR  AND  ITS  COUSINS  67 

reptiles  in  the  return  of  the  conditions  of  the  golden 
age.  There  was  again  plenty  of  water,  warmth,  and 
food.  Early  in  the  Mesozoic  Age  they  spread  over 
the  earth,  and  grew  to  enormous  proportions,  owing 
to  the  abundance  of  food  and  the  relative  scarcity  of 
enemies.  "Amphibian"  to-day  means  to  us  a  frog 
or  toad  or  newt,  a  small  and  despised  thing.  In  the 
Mesozoic  Age  you  might  have  met  one  peeping  out  of 
the  water-vegetation  with  a  head  three  feet  long  and 
two  feet  wide.  But  the  reptiles  occupied  the  same 
world  as  they  did,  and  had  greater  advantages. 
The  amphibians  grew  less  numerous  and  smaller, 
approaching  more  and  more  to  the  types  that  we 
know  to-day. 

The  insect  world  was  developing,  and  we  will  con- 
sider this  later.  In  the  waters  the  population  was 
making  the  same  steady  and  sanguinary  progress. 
The  fishes  made  great  advances,  the  types  with  bony 
skeletons  now  appearing  for  the  first  time.  Most 
people  are  so  familiar  with  fish  bones  that  they  can 
hardly  think  of  a  fish  without  them.  Many  know, 
however,  that  fishes  of  the  skate  family  have  not 
real  bones,  but  a  frame  of  cartilage.  As  we  should 
naturally  expect,  the  earlier  fishes  had  skeletons  of 
cartilage,  which  always  precedes  bone. 

But  the  waters  were  now  a  worse  scene  of  terror 
than  ever.  New  types  of  shark,  with  the  formidable 
cutting  teeth  of  our  shark,  though  enormously  larger, 
had  been  evolved.     In  addition  to  these  there  were 


68  THE  BRONTOSAUR  AND  ITS  COUSINS 

now  the  swimming  reptiles,  some  of  which  had,  as 
I  said,  swift  fish-like  paddles,  eyes  fifteen  inches  in 
diameter,  and  crocodile-like  jaws  adorned  with  about 
two  hundred  teeth.  We  do  not  wonder  that  the 
geological  chronicle  shows  a  rapid  improvement  of 
the  fishes — especially  of  their  power  of  getting  away — 
but  we  will  not  go  into  the  details. 

Every  section  of  living  nature  had  new  terrors  and 
new  enemies.  There  was,  as  yet,  no  social  life,  except 
among  such  animals  as  corals  and  sponges  and  polyps, 
which  have  no  intelligence  (and  most  probably  no 
consciousness  whatever)  to  profit  by  it.  Carnage,  and 
changes  of  land  and  water,  were  the  great  stimulants. 
Besides  the  sharks  and  Ichthyosaurs,  for  instance, 
there  now  appeared  in  the  ocean  the  king  of  the 
shell-fish  family,  the  Ammonite.  He  lived  in  a  great 
curved  shell,  like  a  coiled  snail's  shell,  which  was 
sometimes  three  or  four  feet  in  diameter.  At  the 
opening  of  this  he  watched  for  his  prey,  with  great 
eyes  and  a  huge  expectant  mouth.  He  greatly  helped 
the  world  of  small  invertebrate  animals  of  the  sea  to 
move  on  to  a  higher  level. 

But  we  will  keep  to  the  broad  lines  and  general 
principles  of  the  subject.  This  Mesozoic  Era  was,  as 
I  said,  a  period  of  reaction  between  two  revolutions. 
With  the  second  revolution  we  open,  not  exactly  the 
modern  period,  but  the  period  of  the  ancestors  of  our 
modern  types,  and  we  move  in  a  world  that  is  less 
strange.      The  revolution  was,   of  course,   another 


THE  BRONTOSAUR  AND  ITS  COUSINS  69 

severe  chill  of  the  face  of  the  earth.  There  are 
traces  of  glaciers  here  and  there,  but  they  do  not 
amount  to  very  much,  and  we  do  not  speak  of  an 
Ice  Age.  But  there  is  a  real  revolution  in  the  life  of 
the  planet.  The  Mesozoic  Era  ends  with  the  time 
when  the  great  chalk-beds,  composed  of  the  "  .shells  " 
of  m3rriads  of  dead  animalcules,  are  laid  down  on  the 
floor  of  the  ocean.  During  this  Cretaceous  (Chalk) 
Period  there  is  a  slow  transformation  of  the  world  of 
life.  The  great  reptiles  disappear;  and  most  of  the 
smaller  t3^pes,  the  survivors  of  that  powerful  dynasty, 
retire  into  the  tropics.  This  obviously  means  a  chill. 
The  north  is  too  cold  for  them,  food  is  less  abundant, 
and  leaving  eggs  to  the  care  of  nature  is  no  longer 
possible.     Cold  killed  the  reptilian  monsters. 

At  the  same  time,  naturally,  we  find  an  expansion 
of  the  birds  and  mammals.  Not  only  are  their  fierce 
enemies  removed,  but  the  conditions  for  which  they 
are  particualrly  fitted — cold  climate  and  brisk  move- 
ment— return  to  the  earth.  It  is  a  good  example  of 
what  we  mean  by  "survival  of  the  fittest."  In  the 
Mesozoic  Age  the  reptiles  were  fitter  than  the  birds 
and  mammals.  The  latter  were  far  superior  in  brain 
and  organization,  yet  they  were  the  less  fit  for  those 
particular  conditions.  When  the  cold  returned,  the 
conditions  of  the  struggle  were  reversed.  The  huge, 
heavily  armed,  and  armoured  reptiles  were  the 
**  unfit."  In  spite  of  all  their  strength,  they  gave  way 
to  tiny,  rabbit-like  creatures  and  birds. 


70  THE  BRONTOSAUR  AND  ITS  COUSINS 

There  is  a  corresponding  change  in  the  earth's 
vegetation.  Up  to  this  point  it  has  been  an  evergreen 
earth.  There  was  no  winter,  no  need  to  shed  the 
leaves  once  a  year.  Now,  in  the  Chalk  Period,  we 
find  in  America  the  traces  of  trees  which  shed  their 
leaves  periodically.  Winter  has  become  an  institution 
of  the  northern  hemisphere.  Before  the  end  of  the 
period  we  find  the  older  types  of  trees  giving  way  to 
the  willow  and  birch,  the  oak  and  mulberry,  the 
laurel  and  myrtle,  the  maple  and  elm,  the  walnut, 
and  dozens  of  other  familiar  trees.  New  flowers  in 
great  variety  appear.  We  will  consider  this  opening 
of  our  modem  world  in  the  next  few  chapters. 


CHAPTER  VII 

THE  EVOLUTION  OF  THE  FLOWERS 

The  reader  may  now  begin  to  understand  the  large 
variety  of  living  nature.  But  there  are,  as  I  know 
from  questions  at  the  close  of  lectures  on  Evolution, 
always  a  few  who  say  that  this  variety  is  puzzling 
from  another  point  of  view.  Why  do  the  older  types 
of  animals  and  plants  remain  at  all?  One  can  under- 
stand that  in  the  beginning  all  animals  and  plants 
were  ** microbes"  (single  cells).  One  can  follow  the 
story  when  the  man  of  science  says  that  life  later 
rose  to  the  level  of  the  ferns  and  mosses,  the  jelly- 
fishes  and  corals;  later  again  to  that  of  reptiles  and 
cycads;  still  later  to  that  of  roses  and  eagles  and 
men.  But  why  did  not  the  whole  world  move  on? 
Why  did  not  ferns  and  salamanders  and  lung-fishes, 
etc.,  die  out  when  they  gave  birth  to  higher  forms? 
Or  why  did  they  not  all  evolve  ? 

One  has  only  to  take  a  simple  and  important  ex- 
ample, and  the  answer  is  plain.  The  fishes  gave  birth 
to  the  land  animals,  which  are  much  higher.  But  it 
would  be  obviously  absurd  to  expect  the  fishes  then 
to  die  out,  or  all  to  leave  the  ocean.  The  waters  re- 
mained their  natural  and  sufficient  home,  while  the 

71 


^2  THE  EVOLUTION  OF  THE  FLOWERS 

land  provided  a  new  home  for  the  ''surplus  popula- 
tion." One  might  as  well  say  that  Englishmen  ought 
to  have  died  out  when  they  sent  colonists  to  America 
and  Australia !  This  is  the  principle  to  bear  in  mind : 
The  old  or  original  environment  remains  good  for  the  old 
type.  The  new  type  may  even  live  in  the  same  region, 
but  it  has  new  habits  or  a  new  diet.  Nature  really 
provides  half-a-million  environments.  So  you  get 
half-a-million  species  in  them.  There  is  life  wherever 
there  is  an  environment. 

This  is  quite  plain  in  the  case  of  the  plants,  which 
we  are  now  going  to  consider.  Omitting  the  micro- 
scopic and  other  early  types,  there  was  a  time  when 
none  existed  above  the  specimens  of  what  you  may 
broadly  call  the  '* sea-weed."  Some  of  these  invaded 
the  land,  and  were  gradually  transformed,  in  the  new 
conditions,  into  ferns  and  mosses.  But  this  did  not 
make  the  least  difference  to  the  sea- weeds  themselves. 
The  sea  was  as  good  a  world  as  ever  for  them.  In 
course  of  time  the  ferns  and  mosses  begot  higher 
types.  But  the  particular  sphere  of  ferns  and  mosses 
remained.  Your  humble  moss  is  still  monarch  of  its 
own  environment;  say,  the  moist,  shaded  hillside.  It 
is  particularly  fitted  for  that  world,  and  thrives  there 
better  than  higher  plants  would.  The  pine  and  yew 
were  born  of  a  remote  Ice  Age.  But  there  are  plenty 
of  cold  and  hardy  regions  for  them,  and  they  remain. 

Thus,  while  the  plant  world  has  been  marching  on 
through  the  ages,  it  has  like  the  animal  world,  left 


THE  EVOLUTION  OF  THE  FLOWERS  73 

regiments  behind  at  each  station,  as  it  were,  and 
these  represent  the  stages  of  advance.  A  micro- 
scopist  will  show  you  in  a  drop  of  pond-water  the  tiny 
one-celled  algcB  which  remain  at  the  lowest  level  of 
plant-life ;  and  he  may  then  show  you  chains  or  clusters 
of  alg(E,  representing  the  next  great  step,  the  forma- 
tion of  a  many-celled  body.  The  botanist  would  then 
show  you  how,  in  the  course  of  time,  some  of  the  cells 
"specialize."  Some  make  the  stem,  some  the  leaves, 
some  the  roots,  some  the  spores  or  seed. 

But  I  have  not  space  here  to  consider  the  very  rich 
evolution  of  the  plant  world.  If  I  gave  only  a  general 
outline  of  it,  the  result  would  be  a  bewildering  variety 
of  technical  names.  Some  teachers  think  it  real  in- 
struction to  insist  on  a  certain  number  of  technical 
names.  It  is  not,  unless  a  pupil  is  definitely  learning 
a  particular  branch  of  science.  These  names  cause 
brain-fog,  unless  they  are  thoroughly  learned  and 
analysed.  That  is  good  in  its  place,  but  this  is  not 
the  place  for  it.  We  will  rather  make  a  general 
survey  of  the  evolution  of  flowers. 

The  various  parts  of  a  flower  are  leaves  which  have 
been  modified  for  their  particular  purposes  in  the 
course  of  evolution.  In  a  growing  flower  or  a  very 
primitive  flowering  plant  a  botanist  can  clearly 
demonstrate  this.  Here  we  will  take  it  for  granted. 
The  lower  types  of  plants  have  spores,  not  seed,  and 
no  flowers ;  but  it  was  found  some  years  ago,  on  ex- 
amining certain  ferns  which  were  beautifully  pre- 


74  THE  EVOLUTION  OF  THE  FLOWERS 

served  in  the  coal,  that  they  had  seed  and  seed  organs 
instead  of  the  usual  spores.  They  were  branching, 
as  all  living  families  do.  One  branch  of  the  coal 
forest  plants  was,  under  the  stress  of  the  Ice  Age, 
going  to  produce  the  pine  and  fir,  the  cones  of  which 
are  neither  flowers  nor  spores.  Another  branch,  the 
seed-bearing  ferns,  was  going  to  produce  the  flowering 
plants.  ^ 

The  crude  green  "flowerets"  of  these  seed-bearing 
ferns  are  almost  lost  in  the  confusion  of  the  Permian 
Revolution,  and  it  would  be  a  sin  against  the  purpose 
of  this  little  book  to  follow  botanists  in  their  learned 
attempts  to  trace  the  evolution.  It  is  enough  that 
the  Ice  Age  closed  the  long  reign  of  the  lowly  spore- 
bearing  plants,  and  opend  the  era  of  flowering  plants 
and  conifers.  We  saw  the  Mesozoic  plains  were 
covered  with  Cycads,  palm-like  plants  with  crude 
types  of  flowers,  or  "fructifications."  The  colours  we 
can  only  estimate.  Probably  at  first  they  were  pre- 
dominantly green,  and,  as  time  went  on,  yellow  gained 
upon  the  green.  It  is  not  thought  that  these  were 
the  parents  of  our  flowering  plants.  Probably  some 
hardy  seed-bearing  type  of  fern  remained,  during  the 
age  of  the  great  reptiles,  on  higher  and  cooler  levels, 
waiting,  like  the  bird  and  mammal,  for  the  return  of 
the  cold. 

^  See,  for  a  short  and  authoritative  account,  D.  H.  Scott's  Evolu- 
tion of  Plants  (in  the  "Home  University  Library").  It  is  not 
simple  reading. 


THE  EVOLUTION  OF  THE  FLOWERS  75 

The  cold  of  the  Chalk  Period  gave  them  their  oppor- 
tunity. Then,  as  we  saw,  the  flowering  trees  and 
plants  spread  from  eastern  America,  which  seems  to 
have  been  higher  than  the  west,  and  over  the  whole 
northern  hemisphere.  There  was  still  land  across 
the  northern  Atlantic,  and  in  the  very  slow  way  of 
forests  they  gradually  reached  and  overran  Europe. 
Not  only  the  trees  I  named,  but  the  oleander  and 
magnolia,  the  palm  and  the  grass,  the  lily  and  orchis 
and  iris,  now  came  upon  the  stage.  From  green  the 
earth  had  turned  partly  yellow.  From  yellow  it  now 
turns  white. 

As  flowers  are  not  fossilized,  one  is  often  asked  how 
we  know  that  there  were  these  successive  waves  of 
colour.  It  is,  of  course,  an  inference;  but  it  has  good 
grounds.  If  you  arrange  a  large  number  of  flowers 
according  to  their  degrees  or  stages  of  organization — 
according  to  the  complexity  or  simplicity  of  their 
seed  organs,  petals,  and  sepals — you  will  find  a  pro- 
nounced colour  scheme.  The  simplest  are  predomi- 
nantly yellow  (green  at  first).  Those  of  the  next 
stage  of  organization  are  mainly  white,  with  some  red. 
The  colour  red  predominates  in  the  next  group ;  and 
at  the  top  you  get  blue  and  variegated  flowers.  As 
this  corresponds  with  their  evolution  in  time,  the  sim- 
plest naturally  coming  first,  we  gather  the  successive 
appearances  of  the  colours  in  nature. 

It  may  also  be  asked  how  we  can  read  the  change 
of  climate  from  the  appearance  and  trivimphant 


76  THE  EVOLUTION  OF  THE  FLOWERS 

spread  of  our  higher  flowering  trees.  This  is  simple 
when  one  learns  why  a  tree  sheds  its  leaves  in  the 
winter.  The  leaves  are  more  or  less  the  lungs  of 
the  tree.  Through  them  it  gives  off  moisture.  In  the 
winter,  however,  it  receives  little  or  no  moisture  from 
its  roots,  according  to  the  state  of  the  ground,  and 
the  leaves  are  sacrificed  in  order  to  preserve  the 
moisture  in  the  tree.  Here,  again,  one  sees  the  last 
term  of  a  long  evolution.  The  various  steps  of  it 
have  been  lost.  It  may  have  taken  place  on  *'the 
Lost  Atlantis."  ^  In  any  case,  when  we  do  find  these 
"deciduous"  (leaf -shedding)  trees  appearing  in  the 
Chalk  Period,  we  know  the  meaning.  The  earth  is 
growing  colder ;  winter  has  begun. 

But  the  great  chill  which  killed  the  reptiles  and 
opened  the  reign  of  the  birds,  mammals,  and  flowering 
plants  melted  away  again  like  its  predecessors.  The 
temperature  of  even  the  northern  hemisphere  rose  so 
high  that  magnolias,  figs,  and  bamboos  flourished  in 
Greenland,  where  men  can  now  barely  wrest  their 
remains  from  the  frozen  soil.  Palms  and  aloes 
flourished  in  France.  Warm-loving  animals  wandered 
as  far  north  as  Scotland.  It  was  not  so  warm  as  it 
had  been  in  the  earlier  periods,  and  from  this  point 
onward  the  earth  becomes  increasingly  cooler;   but 

^  I  use  the  name  fancifully  for  the  continent  which  so  long  did 
exist  across  the  North  Atlantic.  But  it  disappeared  before  the 
coming  of  man,  or  at  least  long  before  civilization,  and  there  is  no 
foundation  for  the  Greek  legend  of  a  Lost  Atlantis. 


THE  EVOLUTION  OF  THE  FLOWERS  77 

the  genial  climate  of  the  whole  earth  lasted  long 
enough  to  permit  a  great  expansion  of  the  flowering 
plants.  The  landscape  slowly  took  on  the  features 
which  make  it  familiar  to  us  to-day.  But  the  world 
was  to  pass  through  a  mightier  chill  than  ever  before 
its  modern  appearance  would  be  finally  reached. 

At  the  time  of  the  spread  of  the  flowering  plants 
there  was  also  a  rapid  evolution  of  the  insect  world. 
Now  the  bees  and  wasps,  ants  and  flies  and  butterflies, 
came  upon  the  scene.  We  saw  that  the  coal  forests 
had  had  only  primitive  large  flying  insects,  beetles, 
and  other  lowly  types.  We  saw  that  wings  are 
developed  frequently  in  the  course  of  evolution. 
Wherever  there  is  a  great  struggle  for  life,  some  of 
the  hunted  will  try  to  escape  into  the  broad  free  at- 
mosphere which  floats  above  the  teeming  ground. 
Even  fishes,  in  the  tropics,  have  developed  a  certain 
power  of  flying,  or  rather  "planing,"  away  from  their 
enemies;  and  to  see  a  flock  of  these  ''flying  fishes" 
rise  out  of  the  water — if  they  are  near  the  ship,  you 
can  sometimes  see  the  dark  shade  of  a  shark  approach- 
ing— gives  one  an  idea  of  the  beginning  of  the  evolu- 
tion of  flight.  You  might  almost  say  that  the  same 
thing  is  happening  under  our  eyes  in  England  to-day. 
Man  is  struggling  to  rise  out  of  his  congested  roads 
and  travel  in  the  free  air.  So  insects,  and  reptiles 
and  birds,  bats  and  ''flying  foxes,"  have  at  different 
times  escaped  from  the  struggle  on  the  ground  by 
developing  wings. 


78  THE  EVOLUTION  OF  THE  FLOWERS 

The  active  flying  insects  naturally  developed  very 
richly  when  the  earth  became  covered  with  iSowers. 
One  has  only  to  watch  the  swarms  of  them  hovering 
about  the  flowers  in  the  summer  to  realize  how  the 
two  worlds  would  grow  simultaneously.  Probably 
everybody  now  knows  that  the  insect  is  useful  to  the 
flower  in  return  for  the  food  it  gets.  It  is  an  advan- 
tage when  the  pollen  of  one  plant  is  taken  to  fertilize 
the  seed  of  another  plant,  instead  of  fertilizing  its 
own  seed.  The  wind  may  perform  this  service,  and 
does  in  the  case  of  some  plants;  but  it  is  a  clumsy 
and  wasteful  process.  It  is  far  more  effective  when 
the  little  bee,  poking  into  the  depths  of  the  flower  for 
the  honey  which  is  prepared  for  it  there,  gets  the 
pollen  on  its  body,  by  rubbing  against  the  stamens, 
and  unconsciously  carries  it  to  the  next  flower. 
This  is  "cross-fertilization,"  which  is  better  than 
self-fertilization. 

It  is  generally  believed  that  the  colours  of  the 
flowers  are  a  sort  of  advertisement  to  the  insects. 
The  yellow  leaves  of  the  buttercup — they  are,  like 
all  other  parts  of  the  flower,  transformed  leaves — 
practically  mean  to  the  distant  insect,  "Free  food 
here."  There  has  been  some  dispute  in  recent  science 
as  to  whether  the  insects  really  are  attracted  by 
colours,  but  the  experiments  that  have  been  made 
seem  to  show  that  this  is  the  case.  Naturally,  the 
insects  and  the  flowers  must  have  developed  together. 
It  takes  ages  to  evolve  any  arrangement  of  this  kind, 


THE  EVOLUTION  OF  THE  FLOWERS  79 

and  it  would  be  very  unscientific  to  imagine  first 
the  flower  world  slowly  evolving  its  attractions, 
and  then  imagine  the  insects  discovering  the 
secret  in  some  wonderful  way.  All  through  the 
period  of  the  great  reptiles,  flowers  and  insects 
and  their  mutual  service  must  have  been  developing 
simultaneously. 

But  the  mighty  expansion  of  the  flowers  after  the 
severe  chill  of  the  Chalk  Period  would  in  turn  lead  to 
a  tremendous  growth  and  rapid  development  of  the 
insects.  We  have  so  often  seen  the  principle  on 
which  the  machinery  of  evolution  works  that  it  is 
hardly  necessary  to  repeat  it  here.  It  is  absurd  to 
imagine  a  "vital  force"  pushing  evolution  in  this  or 
that  direction.  That  is  merely  playing  with  words. 
It  is  equal  to  saying  that  "something  or  other  did 
it,"  and  then  imagining  that  you  have  explained  the 
matter. 

You  understand  it  much  better  when  you  remember 
that  the  flowers  which  were  cross-fertilized  had  the 
best  chance  of  growing  the  next  generation,  and  that 
those  flowers  had  the  best  chance  of  cross-fertilization 
which  provided  sweet  food  for  insects  and  some 
means  of  letting  the  insect  know  that  the  food  was 
there.  Then  imagine  the  broad  sunny  continents  of 
the  Tertiary  Era,  which  we  have  reached,  teeming 
with  flowers.  It  was  still  so  warm,  remember,  that 
figs  and  bamboos  grew  in  Greenland.  There  would 
be  an  intense  struggle   among  the  seed,   and  the 


80  THE  EVOLUTION  OF  THE  FLOWERS 

cross-fertilized  would  have  the  advantage.  Natural 
selection  would  foster  and  increase  every  trick  and 
apparatus  that  led  most  surely  to  cross-fertilization. 

To  work  out  this  principle  in  the  world  of  flowers, 
and  explain  the  wonderful  variety  of  flower  structures, 
would  require  a  whole  large  volume,  or  series  of 
volumes.  One  must  consult  botanical  works.  Here 
we  can  only  consider  broad  features  of  the  evolution 
of  nature.  One  of  these  is  that  the  great  outpouring 
of  the  flowers  came  naturally  after  the  severe  chill 
had  removed  the  large  imperfectly-flowering  plants  of 
"the  Middle  Ages,"  along  with  the  monstrous  reptiles 
and  other  mediaeval  types;  and  that  with  the  expan- 
sion of  the  flowers  came  the  spread  of  the  bees  and 
wasps  and  butterflies. 

You  may  think  that  flies  and  butterflies  cannot  be 
fossilized,  and  so  the  man  of  science  must  be  guessing 
what  happened  millions  of  years  ago.  He  often  does 
guess,  though  he  is  always  careful  to  tell  you  that  it 
is  only  a  guess,  until  he  has  found  positive  evidence 
to  prove  that  his  guess  was  right.  But  here  we  have 
direct  evidence.  Did  you  ever  see  a  piece  of  amber 
with  a  fly  in  it?  There  is  a  shop  near  the  British 
Museum  in  London  where  you  can  buy  one  at  any 
time.  That  fly  may  be  two  or  three  million  years 
old.  Amber  is  more  or  less  fossilized  resin;  and 
ages  ago  the  fly  stuck  on  the  resin,  as  it  oozed  from 
the  tree,  and  was  covered  over  with  fresh  outpours  of 
resin.     Then  the  tree  died  and  the  resin  broke  off; 


THE  EVOLUTION  OF  THE  FLOWERS   8i 

and  it   has   beautifully   preserved   insects   of   three 
million  years  ago  for  us  to  examine. 

In  other  cases  myriads  of  insects  have  fallen  into 
the  mud  at  the  bottom  of  lakes,  and  been  preserved. 
In  some  cases  myriads  have  been  buried  in  the  fine 
ash  of  a  volcano.  We  have  countless  specimens,  and 
they  help  us  to  restore  the  scene  after  the  reptiles 
had  gone.  It  now  had  large  numbers  of  our  familiar 
trees  and  flowering  plants.  It  began  to  have  grass 
on  its  plains.  It  had  bees  and  wasps  and  butterflies 
going  from  flower  to  flower.  Next  we  have  to  bring 
the  birds  on  the  scene,  and  then  we  will  introduce 
our  familiar  mammals  and  man. 

6 


CHAPTER  VIII 

THE  COMING  OF  THE   BIRDS 

We  seem  to  have  neglected  the  birds  for  a  long  time. 
They  had  really  appeared  several  million  years  before 
the  age  we  are  now  considering,  and  it  may  be  sup- 
posed that  such  highly  organized  creatures,  living  in 
the  free  air,  would  have  prospered  and  spread  con- 
siderably diiring  those  millions  of  years.  As  a  matter 
of  fact,  we  find  very  few  remains  of  birds  in  the  rocks 
which  represent  that  very  long  period.  If  the  living 
things  of  that  age  are  buried  in  anything  like  the 
proportion  in  which  they  lived,  there  must  have  been 
extremely  few  birds. 

A  word  of  warning  about  these  "fossil  remains*' 
may  usefully  be  given  here.  Some  people  ask  us 
why,  if  the  animals  of  the  past  are  buried  in  our 
rocks,  we  cannot  find  whole  series  of  remains  showing 
the  gradual  transformation  of,  say,  a  reptile  into 
a  bird  or  a  mammal.  Now,  that  is  one  of  the 
questions  which  ought  not  to  be  asked  by  any  person 
who  makes  a  good  use  of  his  eyes.  Just  look  round 
a  region  that  is  teeming  with  animal  life — say,  a  wood. 
How  many  remains  of  those  myriads  of  insects  and 
birds  and  other  animals  will  there  be  left  in  a  million 

82 


THE  COMING  OF  THE  BIRDS        83 

years?  Probably  none  whatever.  The  bodies  must 
be  deposited  in  certain  rare  conditions  to  be  preserved 
and  "fossilized."  They  must  be  put,  as  a  rule,  in  the 
mud  at  the  bottom  of  stagnant  water.  As  the  vast 
majority  die  on  land,  they  are  not  preserved  at  all. 
Only  a  tiny  fraction  of  the  things  that  have  lived  on 
the  earth  are  thus  preserved. 

So  the  story  of  evolution  as  it  is  written  in  the 
rocks  is  very  imperfect.  Here  and  there  it  is  almost 
complete  for  a  page  or  two.  For  instance,  shell-fish 
are  easily  preserved  in  lakes  and  there  are  cases 
where  we  can  trace  gradual  evolution  for  quite  a  long 
distance.  Sea-urchins  are  easily  preserved  in  chalk- 
ooze,  and  we  can  in  many  cases  follow  their  gradual 
evolution  a  long  way  in  our  chalk  cliffs.  But  these 
are  exceptions.  In  other  cases  the  bones  are  still 
numerous  enough  to  enable  us  to  follow  the  gradual 
evolution  very  fairly.  We  shall  see  this  in  the  case 
of  the  horse  and  the  elephant.  In  most  cases  only 
a  specimen  here  and  there  in  ages  is  preserved,  by 
some  chance  or  other,  and  we  are  lucky  to  get  these. 

That  is  the  situation  as  regards  the  evolution  of  the 
bird.  Only  one  specimen  (or  two  specimens  of  the 
same  bird)  has  been  preserved  in  the  rocks  from 
the  hundreds  of  thousands  of  years  during  which 
a  branch  of  the  reptiles  was  being  transformed  into 
birds.  It  was  found  in  certain  rocks  in  Bavaria. 
Millions  of  years  ago  the  bird  flew  in  the  atmosphere 
of  Europe,  which  was  then  mostly  under  water,  as 


84        THE  COMING  OF  THE  BIRDS 

we  saw,  and  its  body  was  buried  in  a  fine  mud  at  the 
bottom  of  a  lake.  Probably  many  were  so  buried, 
but  most  of  the  rocks  are  still  deep  underground  and 
unexplored,  while  others  have  since  been  ground  up 
and  used  over  agin.  We  were  lucky  to  find  this 
petrified  Archcuopteryx  (Ancient  Bird),  as  it  is  called. 

It  was  about  the  size  of  a  crow,  and  its  various 
parts  have  been  so  finely  turned  into  stone  that,  as  far 
as  external  appearance  goes,  we  might  as  well  have 
the  actual  body.  It  has  the  unmistakable  feathers 
and  wings  of  a  bird.  But  it  is  like  no  bird  in  the 
world  to-day.  It  is  half  a  reptile.  There  is  a  long 
tail,  like  that  of  a  lizard;  a  clear  continuation  of  the 
backbone  far  beyond  the  back  legs,  with  large  feathers 
sticking  out  on  each  side  of  the  tail.  It  has  two  rows 
of  teeth  in  its  jaws;  and  no  bird  in  nature  to-day  has 
teeth.  It  has  also  perfectly  formed  feet  and  claws 
on  its  front  limbs,  its  wings;  and  there  are  very  few 
birds  in  nature  now  which  have  such  toes,  though 
the  majority  have,  underneath  the  skin,  stunted  little 
bones  which  represent  them. 

In  the  early  days  of  evolution  people  used  to  talk 
much  about  "missing  links."  In  this  case  a  very 
important  missing  link  was  recovered.  It  is  the  link 
between  the  reptile  and  the  bird.  If  it  were  not  for 
the  feathers,  we  should  call  it  a  flying  reptile.  It 
perfectly  illustrates  the  gradual  conversion  of  a  reptile 
into  a  bird,  as  we  sketched  it  in  an  earlier  chapter. 

We  saw  that  this  evolution  was  an  outcome  of  the 


THE  COMING  OF  THE  BIRDS        85 

Ice  Age.  In  the  colder  regions  no  ordinary  reptile 
could  live.  The  animal  itself  was  cold-blooded  and 
thinly  clad,  and  it  provided  no  warmth  for  its  eggs  or 
food  for  its  young.  In  the  stress  of  the  struggle  that 
must  have  followed  in  the  overcrowded  warm  regions, 
pioneers  with  favourable  variations  were  able  to 
survive  in  more  temperate  localities.  We  must  not 
suppose  an  animal  suddenly  changing  from  a  three- 
chambered  to  a  four-chambered  heart.  Even  here 
gradual  development  is  not  so  difficult  as  may  be 
imagined.  Some  of  our  reptiles  to-day  have  hearts 
that  are  not  strictly  either  three-chambered  or  four- 
chambered.  There  is  a  sort  of  effort  to  get  a  fourth 
chamber. 

The  feathers  are  less  difficult  to  understand.  They 
are  transformed  scales.  Look  again  at  the  next  hen 
you  see,  and  you  will  notice  that  the  scales  which 
cover  its  legs  really  bring  it  nearer  to  the  reptile  than 
you  had  supposed.  Examine  a  feather,  and  you  will 
see  that  it  is  composed  of  the  same  material.  Feathers 
are  scales  lengthened  and  "feathered,"  if  one  may 
use  the  expression.  The  feather  as  we  know  it  is  the 
outcome  of  millions  of  years  of  an  evolution  which 
aimed  at  combining  warmth  with  lightness.  Even 
the  little  ArchcEOpteryx,  whose  remains  we  have  found, 
does  not  belong  to  the  Ice  Age,  but  a  very  long  time 
afterwards.  Its  feathers  are  well  formed.  There 
must  have  been  myriads  of  earlier  stages,  with  large 
heavy  scales  becoming  gradually  more  "feathery." 


86        THE  COMING  OF  THE  BIRDS 

As  to  the  beginning  of  the  care  of  the  eggs,  we 
have,  naturally,  no  positive  knowledge  whatever. 
Nesting  is  very  varied  in  nature  to-day,  and  is  in 
some  cases  extremely  simple.  I  would  venture  to 
conjecture  that  for  millions  of  years — possibly  until 
the  last  Ice  Age — birds  did  not  nest  at  all.  But  they 
must  have  begun  early  to  brood  over  the  eggs.  If 
the  mother  needed  feathers  to  keep  her  warm,  the 
eggs  needed  warmth  to  hatch.  Here  again  there  is 
not  a  quite  sudden  leap  from  the  reptile  world.  Some 
of  our  living  reptiles  bury  their  eggs  in  a  sort  of 
"nest." 

These  are  merely  general  and  superficial  considera- 
tions. I  am  only  sketching  the  broad  lines  of  develop- 
ment. It  is  not  possible  or  desirable  here  to  go  more 
deeply  into  the  matter.  Special  authorities  on  birds 
must  be  consulted.  I  merely  wish  to  make  the  bird 
world  broadly  intelligible.  Even  children  to-day 
ought  to  know  more  than  that  there  are  birds  because 
there  is  air,  and  fishes  because  there  is  water,  and 
beasts  because  there  is  land.  The  doctrine  of  evolu- 
tion, which  throws  such  a  wonderful  light  on  nature, 
is  shockingly  neglected  in  our  schools.  **  Nature 
study  "  is  a  poor  thing  without  evolution. 

There  are  birds  because  once  upon  a  time  the  earth 
was  for  two  or  three  hundred  thousand  years  in  the 
grip  of  an  Ice  Age,  and  in  some  regions  all  the  higher 
animals  (reptiles)  would  have  perished  if  they  had 
not  developed  the  "heating-apparatus"  of  the  bird. 


THE  COMING  OP  THE  BIRDS        87 

The  mammals  came  for  the  same  reason,  at  the  same 
time,  from  the  same  reptile  world.  But  the  Ice  Age 
melted  away,  as  we  saw,  and  the  birds  and  mammals 
had  no  advantage  in  their  higher  organization.  Fur 
coats,  that  you  could  not  get  rid  of,  were  not  a  good 
equipment  in  an  age  of  warm  perpetual  summer. 
Brooding  over  eggs  was  unnecessary,  and  unnecessary 
labour  is  not  encouraged  in  nature.  So  we  are  not 
surprised  that  bird-remains  are  very  rare.  In  rocks 
which  represent  several  million  years  of  the  Mesozoic 
Era  we  have  found  only  these  two  specimens  of  one 
bird. 

Towards  the  end  of  the  Age  of  Reptiles,  in  the 
Chalk  Period,  we  find  a  few  others.  They  belong  to 
fully-formed  birds  of  quite  different  types,  and  they 
tell  us  that  the  bird  world  was  now  expanding.  The 
earth  was  cooling.  Possibly  the  monstrous  flying 
reptiles,  which  would  gulp  down  one  of  the  early 
birds  like  a  dragon-fly,  were  being  driven  out  of  large 
temperate  regions,  and  making  way  for  the  birds. 
As  soon  as  they  became  lords  of  the  air,  they  would, 
like  all  new  families,  spread  richly,  and  in  different 
directions. 

In  one  feature  the  birds  of  the  Chalk  Period  still 
bear  the  trace  of  their  earthly  ancestry.  They  have 
teeth,  either  separate  real  teeth  or  toothed  jaws.  It 
was  a  matter  of  evolution  and  progress  for  these  teeth 
to  disappear.  They  meant  weight  at  one  end  of  the 
flying  machine;  and  in  the  course  of  development 


88         THE  COMING  OF  THE  BIRDS 

the  bird  became  able  to  grind  its  food  in  its  crop,  and 
thus  dispense  with  the  teeth.  One  of  these  birds  of 
the  Chalk  Period  seems  to  have  lost  the  power  of 
flight,  so  that  we  are  not  surprised  that  it  has  teeth. 
It  was  a  swimming  bird,  like  the  diver,  about  four 
feet  high.  The  other  is  a  small  flying  bird;  though 
it  has  distinct  teeth,  in  sockets,  in  its  jaws. 

These  belong,  as  I  said,  to  the  latter  part  of  the 
Age  of  Reptiles,  when  the  climate  was  growing  colder. 
At  the  close  of  that  period  the  flying  reptiles  perished 
so  completely  that  not  a  specimen  is  left  in  nature 
to-day.  The  air  was  left  to  the  birds  and  insects. 
The  warmth  and  abundance  of  food  returned.  The 
outpouring  of  flowers  fed  the  insects,  and  the  vast 
swarms  of  insects  would  feed  the  birds.  The  rocks 
now  show  a  great  expansion  and  multiplication  of 
species,  which  we  cannot  follow  here  in  any  detail. 
It  is  enough  that  our  familiar  birds  begin  to  appear. 
Ages  before  man  came  along  there  were  owls  and 
parrots  and  many  other  types.  There  were  still  no 
Arctic  regions  or  Alps,  remember;  and  warm-loving 
birds  could  roam  all  over  the  earth. 

In  order  to  throw  a  little  further  light  on  the  bird- 
world  I  will  anticipate  a  little.  For  two  or  three 
million  years  after  the  birds  had  taken  undisputed 
possession  of  the  air  the  climate  of  nearly  the  whole 
earth  remained  more  than  temperate.  Monkeys  lived 
in  what  we  now  call  England.  Elephants  browsed  on 
the  low  hills  which  are  now  the  Dogger  Bank  under 


THE  COMING  OF  THE  BIRDS        89 

the  waters  of  the  North  Sea.  Sea-serpents  wandered 
up  the  mouth  of  the  Thames,  and  rhinoceroses  and 
hippopotami  splashed  in  the  rivers  of  Yorkshire. 

But  the  earth  was  growing  colder.  I  am  not 
satisfied  that  any  good  explanation  has  yet  been 
given  of  this  progressive  cooling  of  our  globe,  and 
I  will  not  speculate  on  it.  Ice  Ages  we  fairly  under- 
stand, as  an  effect  of  the  rise  of  the  land ;  but  general 
cooling  and  the  formation  of  permanent  ice-caps 
at  the  Poles  have  not  yet  been  explained.  We  will 
simply  state  the  fact.  The  northern  hemisphere 
became  more  and  more  temperate.  The  warm- 
loving  plants  and  animals  were  slowly  driven  south. 
The  land  was  rising  in  very  many  parts  of  the  earth. 
The  great  masses  of  the  Rocky  Mountains  and  Andes, 
the  Alps  and  Atlas  and  Himalaya,  were  dtiring  all 
this  time  slowly  rising  towards  the  snow-line.  A  new 
Ice  Age  was  approaching.  This,  of  course,  explains 
much  of  the  cooling  of  the  earth,  but  there  is  a 
steady  lowering  of  temperature  which  it  does  not 
explain.  After  an  Ice  Age  the  earth  never  returns 
quite  to  the  degree  of  warmth  which  it  had  had 
before. 

However,  the  Ice  Age  at  last  set  in.  Seven  million 
square  miles  of  northern  Europe  and  America  were 
covered  with  permanent  ice  and  snow.  Glaciers, 
immensely  larger  than  those  which  now  flow  slowly 
down  the  flanks  of  the  higher  Alps,  flowed  from  the 
hills  of  Scotland,  Cumberland,  and  Wales.     I  will  say 


90        THE  COMING  OF  THE  BIRDS 

more  about  this  later.  It  had  prodigious  influence 
on  animal  and  plant  life,  as  will  be  imagined  after 
our  description  of  the  Permian  Revolution.  This  was 
a  far  greater  Ice  Age. 

Bamboos  and  magnolias  had  long  ago  retired  south. 
Now,  as  the  ice-sheet  spread  south  as  far  as  the  valley 
of  the  Thames  and  the  Danube,  the  whole  population 
fled  before  it.  The  change  was,  as  ususal,  extremely 
slow,  and  the  reader  will  not  misunderstand  when 
I  speak  of  even  the  plant-world  retiring  before  it. 
Only  the  south  of  Europe  and  Africa — they  were  then 
connected  by  land — now  bore  the  wealth  of  flowers  on 
which  the  insects  lived,  and  the  birds  followed  their 
food.  Hardy  types,  the  birds  of  the  Arctic  and 
Antarctic,  were  evolved,  but  the  vast  majority 
retreated  with  the  warmth  and  the  insects. 

Probably  many  features  of  our  insects  and  birds 
were  developed  during  this  long  and  severe  trial.  The 
instinct  of  nesting  would  be  fostered  in  the  birds,  and 
probably  it  was  then  that  the  ants  and  bees  developed 
their  elaborate  ways  of  preparing  against  a  "lean" 
season.  The  migration  of  birds  may  also  receive 
much  light  from  this  geological  event.  It  is  known 
that  migrating  birds  do  not  simply  fly  "somewhere 
south,"  where  there  are  flowers  and  insects.  Each 
family  has  its  winter  resort,  and  they  follow  particular 
and  often  curious  routes  to  it.  It  is  supposed  that 
they  go  back  to  their  homes  in  the  Ice  Age,  and  they 
follow  routes  which  were  at  one  time  "all  land" 


THE  COMING  OF  THE  BIRDS        91 

routes.  There  is  really  no  such  thing  as  "instinct." 
The  habits  of  the  birds  have  been  evolved  under 
pressure  or  guidance  from  without.  So  there  is 
nothing  to  "tell"  them  that  land  and  water  have 
changed  very  much  since  the  days  of  the  Ice  Age, 
and  year  by  year  they  follow  the  old  routes,  many  of 
which  ought  to  have  been  altered  long  ago. 


CHAPTER  IX 

THE  TRIUMPH  OF  THE  MAMMALS 

The  birds  are  our  "sisters"  in  a  way  that  poets  do 
not  know.  We,  the  mammals,  and  they  were  born 
together  of  the  Permian  Revolution.  We  are  the 
common  offspring  of  an  Ice  Age.  That  is  the  original 
reason  why  we  are  ''warm-blooded."  And  warm 
blood  also  means  better  blood,  better  nourished 
brains,  so  that  it  was  a  great  advance  in  organization. 
Surely  these  things  make  nature  more  intelligible 
than  it  was  even  to  the  more  learned  of  our  fore- 
fathers? But  we  will  now  consider  more  closely  the 
origin  and  spread  of  the  vast  mammal  family  to  which 
we  belong. 

Mamma  is  the  Latin  word  for  breast.  Our  very 
young  children  are  not  aware  that  they  are  speaking 
a  famous  dead  language  when  they  address  their 
mothers  by  that  word,  but  it  is  a  fact  that  to  the 
Roman  baby  its  mother  was  above  all  things  a 
mamma — a  breast.  The  mammals  are  therefore  the 
animals  with  breasts;  or,  to  take  their  leading  differ- 
ences from  the  other  Vertebrates,  with  breasts,  a 
womb,  a  four-chambered  heart,  and  a  hairy  coat. 
You  see  at  once  that  all  these  superiorities  mean,  first, 

92 


THE  TRIUMPH  OF  THE  MAMMALS  93 

an  adaptation  to  a  colder  climate.  They  mean  warm 
blood  and  care  of  the  young. 

We  saw  how  the  first  mammals  arose.  One  pro- 
gressive branch  of  the  reptiles,  which  passed  safely 
through  the  sieve  of  natural  selection  during  the 
Permian  Ice  Age,  was  capable  of  being  adapted  to  the 
colder  climate.  It  is  little  use  to  give  you  its  name 
here,  though  scientific  men  are  now  fairly  decided 
which  branch  of  the  ancient  reptiles  it  was  that  took 
this  fortunate  turn.  The  heart  became  four- 
chambered,  and  the  blood  warm.  But  again  there 
was  no  sudden  leap;  in  fact,  there  is  not  in  nature 
to-day  a  perfectly  clean  distinction  between  the  lowest 
mammals  and  the  higher  reptiles.  "Warm  blood" 
means,  as  I  said  before,  that  the  blood  system  has  the 
power  to  keep  the  blood  at  a  fairly  even  temperature 
while  the  temperature  outside  may  vary  considerably. 
In  plain  English,  it  means  having  warm  blood  in  cold 
weather.  The  blood  of  the  reptile  sinks  with  the 
temperature  of  its  surroundings.  That  is  the  chief 
reason  of  the  winter  sleep  of  the  tortoise  or  the  snake. 
But  the  lower  mammals  have  not  entirely  "warm 
blood."  Their  blood  varies  as  much  as  30°  F.  in 
temperature.  They  live  in  Australia  and  New 
Guinea,  and  are  therefore  not  inconvenienced  by 
a  severe  winter.  This  imperfectness  of  their 
machinery  is  quite  a  good  illustration  of  evolution. 

The  fur  coat,  or  coat  of  hair,  is  fully  developed  in 
every  mammal  that  we  know,  and  we  can  only  guess 


94  THE  TRIUMPH  OF  THE  MAMMALS 

how  it  was  evolved.  The  reptiles'  scales  did  not 
evolve  into  hair,  as  those  of  the  ancestor  of  the  bird 
were  transfomred  into  feathers.  Probably  the  hair 
grew  up  out  of  the  skin  underneath  the  scales,  and 
eventually  made  the  scales  superfluous.  When  one 
of  the  lower  (not  the  lowest)  mammals  is  developing 
in  the  womb,  and  the  hair  begins  to  appear,  it  grows 
in  tufts  or  patches,  as  if  each  had  originally  grown 
under  a  scale. 

You  notice  that  in  this  case  I  look  for  guidance 
to  one  of  the  lower,  but  not  lowest,  mammals,  and 
this  may  surprise  you.  The  fact  is  that  the  lowest 
mammal  in  nature  to-day — you  will  be  introduced  to 
it  in  a  moment — has  no  womb  in  which  it  bears  its 
young.  It  lays  eggs,  as  snakes  or  turtles  do.  And 
this  throws  a  very  interesting  light  on  the  evolution 
of  the  third  and  greatest  feature  of  our  mammal 
family,  the  nourishing  of  the  young. 

As  we  saw,  the  mothers  which  would  carry  on  their 
species  through  the  stress  of  the  Ice  Age  must,  if  they 
lived  in  the  temperate  regions,  care  for  their  young. 
The  bird  continued  to  lay  eggs,  but,  unlike  the  reptile, 
provided  warmth  for  them  with  its  own  body.  An 
alternative  way  would  be  to  hatch  the  eggs  inside  the 
mother's  body,  and  this  line  the  mammals  have  fol- 
lowed. Every  animal  that  is  bom  comes  of  an  Qgg\ 
though,  to  use  a  colloquialism,  "there  are  eggs  and 
eggs."  At  first,  however,  the  ancestor  of  the  mammals 
continued  to  lay  eggs,  like  its  reptile  foremothers — I 


THE  TRIUMPH  OF  THE  MAMMALS  95 

nearly  said  forefathers.  But  when  the  eggs  were  laid, 
the  mother  had  a  nest  ready  for  them,  perhaps 
underground,  to  keep  them  warm. 

This  is  the  same  as  the  birds,  you  may  exclaim! 
No;  because  when  the  little  animals  came  from  the 
eggs  the  mother  fed  them  from  her  own  breast.  The 
flesh  and  skin  of  her  breast  were  perforated,  or  had  a 
ntunber  of  large  pores  in  them.  When  the  young 
licked  this  part  of  her  breast,  the  fat-cells  from  her 
blood  oozed  through,  and  the  young  were  nourished. 
It  was  the  primitive  milk.  I  need  not  point  out  the 
great  importance  of  this  change,  and  the  corresponding 
change  made  by  the  bird.  All  animals  had  hitherto 
been  strict  individualists.  There  were,  it  is  true, 
social  groups  of  corals  and  sponges  and  a  few  others; 
but  these  have  no  consciousness  at  all  of  their 
"socialism."  All  parents  among  the  higher  animals 
were  purely  selfish,  and  took  no  care  of  their  eggs  or 
young.  There  was  no  need.  Mother  earth  provided 
everything.  From  this  time  onward  there  is  at  least 
a  link  of  mother  and  young,  a  beginning  of  social 
emotion.     You  see  what  an  Ice  Age  can  do ! 

But  how  do  we  know  all  this  if,  as  I  said,  the  Per- 
mian Ice  Age  was  at  least  nine  or  ten  million  years 
ago?  Even  if  we  had  found  a  fossil,  like  that  of  the 
"Early  Bird,"  we  could  not  possibly  infer  from  it  half 
of  what  I  have  described.  It  is  true  that  we  could 
not  from  the  bones  alone.  Some  writers  credit  men 
of  science  with  almost  magical  powers.     There  is  a 


96  THE  TRIUMPH  OF  THE  MAMMALS 

story  still  in  circulation  that  a  distinguished  man  of 
science  once  said  that,  if  you  gave  him  a  single  bone 
of  some  dead  animal,  he  could  build  up  the  whole 
body.  Scientific  men  are  far  more  modest.  A  few 
years  ago  they  found  the  better  part  of  a  battered 
himaan  skiill  in  Sussex,  but  they  are  disputing  to  this 
day  how  the  missing  parts  of  that  skull  ought  to  be 
filled  in. 

Now,  of  the  early  mammals  we  have  only  a  few 
small  bones  in  the  rocks,  and  they  would  not  tell  us 
much  by  themselves.  But  you  remember  how  we 
were  able  to  describe,  in  the  fourth  chapter,  the  fishes 
which  ten  millions  of  years  ago  left  the  water  and 
began  to  live  on  land.  Remnants  of  that  primitive 
family,  the  lung-fishes,  still  survive  in  nature. 
Animals  of  this  kind  are  often  called  "living  fossils." 
They  help  us  even  more  than  fossils  do.  No  speci- 
mens of  the  earliest  birds  have  survived  in  nature, 
and  we  should  know  very  little  about  them  if  we  had 
not  been  so  lucky  as  to  find  the  two  fossil  birds  in 
Bavaria.  But  with  the  mammals  it  is  quite  different. 
Nature  has  preserved  specimens  of  them  alive  for  us. 

We  are  fond  of  saying  that  nature  "does"  this  or 
the  other.  Of  course,  it  is  literally  true,  as  all  the 
forces  and  causes  or  agencies  that  we  know  belong  to 
nature.  But  even  children  ought  to  be  warned  against 
the  practice  of  thinking  that  "nature"  has  intentions. 
Take,  for  instance,  this  preservation  of  the  early 
mammals  all  through  several  millions  of  years.     It 


THE  TRIUMPH  OF  THE  MAMMALS  97 

v/ill  give  another  glimpse  into  the  machinery  of 
nature  if  we  describe  it. 

At  the  time  when  the  earliest  mammals  appeared, 
towards  the  end  of  tlie  Permian  Ice  Age,  South  Africa 
and  Australia  were,  as  we  saw,  connected  by  land.  It 
was  in  that  part  of  the  world  that  the  little  early 
mammals  lived.  We  find  their  bones  in  South  Africa 
and  their  living  representatives  in  Australia  and  New 
Guinea.  They  wandered  from  Africa  to  Australia; 
or,  as  is  more  probable,  they  were  evolved  on  the  lost 
continent,  which  is  now  beneath  the  waves  of  the 
Indian  Ocean,  and  travelled  east  and  west.  Anyhow, 
they  overran  the  country  which  we  now  call  Australia. 
But  during  the  Age  of  Reptiles  the  land  between 
Africa  and  Australia  foundered.  One  might  almost 
say  that,  when  the  early  mammals  reached  Australia, 
the  gates  were  closed  behind  them.  Australia  became 
an  island.  So  when,  in  the  course  of  time,  lions  and 
tigers  and  other  carnivorous  mammals  were  evolved 
in  the  rest  of  the  world,  they  could  not  reach  Australia, 
and  its  very  primitive  population  slumbered  on  until 
early  man  and  his  dog  came  along  to  disturb  them. 

That  is  why  we  find  primitive  mammals  in  Aus- 
tralia. The  most  primitive  is  a  small  furry  creature, 
about  the  size  of  a  rabbit,  which  is  often  called  in 
English  nature  books  the  "Duckmole,"  because  it 
has  a  beak  something  like  the  duck's  and  it  burrows 
in  the  banks  of  the  streams.  Australians  generally 
call  it  the  Platypus,  or,  if  they  have  been  to  Melbourne 


98  THE  TRIUMPH  OF  THE  MAMMALS 

or  Sydney  University,  they  call  It  the  Ornithorhyncus 
("Bird  Nose").  In  describing  the  life  of  the  early 
mammals  at  the  beginning  of  this  chapter  I  described 
the  Platypus.  It  makes  a  nest  in  its  burrow,  and 
lays  eggs  in  the  nest.  When  the  young  are  born 
they  lick  the  mother's  breast,  and  they  are  nourished 
by  the  fat  (milk)  which  oozes  through  the  pores.  So 
the  Duckmole  is  a  reptile  is  so  far  as  it  lays  eggs, 
which  no  other  mammal  in  the  world  does,  but  a  true 
mammal  because  it  suckles  its  young. 

There  is  a  very  different  animal  of  the  same  family, 
the  Spiny  Ant-Eater,  in  New  Guinea;  but  we  will 
pass  on  to  the  next  stage.  As  everybody  knows,  the 
native  animal  population  of  Australia  consists  entirely 
of  pouched  animals  like  the  kangaroo.  There  is  a 
wild  dog,  or  Dingo,  that  has  puzzled  naturalists  a 
good  deal;  but  on  the  whole  it  seems  to  have  been 
introduced  by  early  man,  who  must  have  been  in 
Australia  a  quarter  of  a  million  years  ago.  The  na- 
tive population  are  kangaroos,  wallabies,  and  other 
animals  which  are  distinguished  by  the  mother  carry- 
ing her  young  in  a  pouch  in  front  of  her  belly. 

The  reason  for  this  peculiar  arrangement  is  very 
interesting.  Most  people,  even  children,  know  that 
the  young  of  one  of  the  ordinary  mammals — a  kitten, 
puppy,  whale,  or  human  being — is  formed  in  the 
mother's  womb,  and  built  up  on  her  blood.  Certain 
blood-vessels  connect  the  little  body  in  the  womb 
with  the  mother's  blood-vessels.     The  child  is  "blood 


THE  TRIUMPH  OF  THE  MAMMALS  99 

of  her  blood."  The  kangaroo  mother  has  not  got 
these  blood-vessels.  She  cannot  nourish  the  body  of 
her  young  with  her  blood.  She  goes  a  step  beyond 
the  Platypus,  it  is  true.  She  hatches  the  eggs  inside 
her  own  body;  but  when  they  are  hatched — when  all 
the  nourishment  in  the  Qgg  has  been  used  up — she 
can  do  no  more  in  her  womb.  The  very  tiny  and 
imperfect  young  are  born.  Naturally,  they  would  die 
if  left  to  themselves.  She  takes  them  in  her  mouth, 
puts  them  in  her  pouch,  and  there  they  hang  on  to 
her  breasts  (which  are  low  down)  until  they  are  fully 
formed. 

Here  is  the  next  stage  in  the  formation  of  a 
mammal;  and  we  are  much  obliged  to  Australia 
for  preserving  these  ancient  curiosities  for  us.  The 
higher  mammals  are  so  much  more  perfect  in  their 
arrangement  for  the  birth  of  the  young  that  these 
primitive  mammals  would  not  be  able  to  stand  compe- 
tition with  them.  The  waters  of  Australia  kept  them 
away.  For  science  the  Platypus  and  the  kangaroo 
are  extremely  interesting;  and  there  is  a  third  type 
which  is  in  some  respects  between  the  two.  We  do 
not  say  that  they  are  the  ancestors  of  the  mammals, 
but  they  are  precious  remnants  of  the  great  family  of 
early  mammals  of  the  Age  of  Reptiles,  and  they  beau- 
tifully illustrate  the  evolution  of  the  mammal  body. 

During  the  Age  of  Reptiles,  as  we  saw,  their  higher 
organization  was  of  no  service,  and  they  lived  an 
obscure,  hunted  life  and  made  little  progress.    Then 


loo  THE  TRIUMPH  OF  THE  MAMMALS 

came  the  great  chill  of  the  Chalk  period  and  the  re- 
moval of  the  giant  reptiles.  The  African  branch  of 
the  family  now  began  to  go  ahead,  while  the  Australian 
branch  remained  nearly  stationary  (as  isolated  popu- 
lations generally  do) .  Towards  the  end  of  the  Chalk 
Period,  and  in  the  next  geological  period,  we  find  so' 
rapid  and  rich  an  expansion  of  the  mammals  that  it 
is  impossible  to  give  even  a  summary  account  of  it 
here.     We  must  be  content  with  a  simple  outline. 

As  I  said,  we  do  not  regard  the  living  duckmole 
and  kangaroo  as  ancestors  of  the  mammals.  The 
kangaroo  (and  pouched  animals,  or  ''Marsupials," 
generally)  is  clearly  a  side-line.  The  duckmole  is 
a  better  specimen  of  an  early  ancestor,  if  you  omit 
the  "beak"  and  other  features  which  were  developed 
later.  From  something  like  the  duckmole,  at  all 
events,  a  slightly  higher  type  of  mammal,  building 
up  its  young  in  its  womb,  developed  in  Africa,  and 
travelled  north.  These  early  mammals  were  probably 
"arboreal  and  insectivorous";  they  lived  in  trees  and 
fed  on  insects.  When  their  Golden  Age  dawned  they 
multiplied  rapidly,  and,  as  we  have  seen  so  often, 
soon  experienced  a  heavy  struggle  for  life,  and  evolved 
in  different  directions.  From  eating  insects  some 
developed  a  taste  for  larger  game,  and  the  familiar 
contest  of  the  vegetarian  and  the  carnivore  set  in. 

The  development  of  the  carnivores  can  be  very 
fairly  traced  by  the  rich  fossil  remains.  Apart  from 
the  seals  and  walruses,  which  retired  to  the  ocean 


THE  TRIUMPH  OF  THE  MAMMALS  loi 

from  the  grim  struggle  on  land,  the  carnivores  are 
now  mainly  divided  into  a  "dog"  family  and  a  "cat" 
family.  We  have  the  common  ancestors  of  these, 
and  can  satisfactorily  trace  the  evolution :  the  bears, 
dogs,  wolves,  foxes,  otters,  jackals,  badgers,  etc.,  on 
the  one  hand,  and  the  lion,  tiger,  leopard,  lynx, 
hy^na,  mongoose,  etc.,  on  the  other.  In  the  early 
period  we  have  carnivores  with  the  general  features 
of  the  various  types  in  one  body,  and,  slowly,  in  the 
course  of  two  or  three  million  years,  the  specific 
types  are  shaped.  There  were  at  an  early  date  even 
fiiercer  carnivores  than  now.  At  one  time  there  was 
a  large  lion-tiger  (the  "Sabre-Toothed  Tiger,"  it  is 
often  called),  with  canine  teeth,  of  terrible  strength, 
seven  or  eight  inches  long. 

These  carnivores  I  take  first  because  they  help  us 
to  understand  the  rest  of  the  mammal  family.  They 
proved  to  be  the  customary  grisly  machinery  of 
natural  selection.  Largely  in  the  attempt  to  get 
away  from  them,  as  well  as  to  avoid  competition  for 
food,  the  rest  of  our  mammals  spread  in  all  directions. 
Moles  and  rabbits  found  refuge  underground.  Hedge- 
hogs and  porcupines  developed  their  barbed-wire 
entanglements.  Squirrels  remained  in  the  trees  and 
obtained  their  great  agility.  Shrews  took  to  the 
streams;  porpoises  and  whales  to  the  sea.  Some 
(lemurs,  bats,  etc.)  adopted  night  life,  instead  of  day 
life.  Some  of  the  carnivores  did  the  same,  and  new 
and  more  wonderful  devices  had  to  be  evolved. 


102  THE  TRIUMPH  OF  THE  MAMMALS 

The  great  order  of  the  Ungulates  (hoofed  animals) 
spread  over  the  four  continents,  and  generally  de- 
veloped speed.  The  hippopotamus  relied  on  bulk, 
and  life  in  the  water.  The  rhinoceros  got  bulk,  a 
good  coat  of  mail,  and  a  horn.  The  elephant  also 
had  weight,  a  fair  speed  in  case  of  need,  and  a  pair 
of  very  formidable  canine  teeth  (tusks).  But  the 
majority  developed  high  speed  and  keen  scent. 

The  ancestors  of  all  these  hoofed  animals  had  five 
toes  on  each  foot.  We  have  numbers  of  remains  of 
them;  and  there  is  a  little  animal  in  Africa  to-day, 
the  Hyrax,  which  goes  back  a  long  way  towards  them, 
as  it  had  four  toes  on  the  front  feet  and  three  on  the 
hind  feet.  But  you  have  only  to  count  the  toes  of 
your  cat,  and  remember  that  carnivores  and  vege- 
tarians had  a  common  ancestor,  to  realize  this. 
Running  tends  to  reduce  the  number  of  toes.  If  you 
watch  an  athlete  waiting  for  the  pistol  at  the  begin- 
ning of  a  race,  3^ou  see  how  he  stands  "on  tiptoe." 
In  running  the  weight  of  the  body  is  lifted  as  much 
as  possible  off  the  soles  of  the  feet  and  thrown  on  the 
toes.  And  if  the  toes  are  like  the  human  fingers, 
longer  in  the  centre  and  shorter  at  the  sides,  the 
weight  is  thrown  on  the  central  toes,  and  the  side  toes 
disappear.  The  horse  became  in  time  a  three-toed 
animal,  as  the  rhinoceros  is.  But  the  ancestors  of 
the  rhinoceros  stopped  there,  and  developed  bulk  and 
armour.  The  ancestors  of  the  horse  continued  to 
rely  on  flight,  two  further  toes  disappeared,  and  the 


THE  TRIUMPH  OF  THE  MAMMALS  103 

modern  horse  with  one  toe  and  one  toe-nail  (hoof) 
was  born. 

We  can  in  the  same  way  trace  the  evolution  of 
most  of  the  mammals.  We  have  found  the  bones  of 
the  ancestors  of  the  elephant  for  many  generations, 
and  can  say  how  its  trunk  was  developed.  We  find 
its  canine  teeth  growing  steadily  longer.  Perhaps 
they  were  used  for  digging  succulent  roots.  The 
nose,  to  be  of  any  use,  had  to  keep  pace  with  the 
teeth  in  length,  and  the  chin  grew  out  to  the  same 
length  to  bear  the  weight  of  the  nose.  When  nose, 
teeth,  and  chin  became  about  a  foot  long,  the  nose 
(or  trunk)  developed  powerful  muscles  attaching  it  to 
the  skull.  The  chin  again  retired — we  trace  all  this 
in  fossil  elephants — and  the  elephant  was  left  with 
two  very  long  teeth  and  a  very  long  nose. 

In  much  the  same  way,  we  can  trace  the  evolution 
of  the  camel,  the  bear,  the  seal,  the  dog,  the  cat,  the 
pig,  and  so  on.  We  can  follow  the  development  of  all 
the  bewildering  varieties  of  teeth,  of  claws,  of  limbs, 
of  hairy  coats,  of  horns,  of  eyes,  of  noses,  of  breasts, 
etc.  Food  and  safety  are  the  keys  to  most  of  their 
structures.  Sexual  selection — the  choice  of  a  mate 
with  certain  features— explains  other  things:  the 
smooth  face  of  some  monkeys,  the  lion's  mane,  and 
other  features.  Evolution  is  the  great  key.  It  puts 
together  the  jig-saw  puzzle  of  nature  as  no  other 
human  thought  ever  did. 

"Struggle"  is  only  part  of  the  mechanism.    We 


104  THE  TRIUMPH  OF  THE  MAMMALvS 

have  to  keep  our  eyes  wide  open  in  studying  evolu- 
tion, as  there  are  numbers  of  different  influences  at 
work  all  the  time.  The  changes  of  land  and  water 
continued.  All  through  the  time  of  the  evolution  of 
the  mammals  the  land  was  rising.  It  made  a  great 
difference  to  many  of  them.  Vegetation  also,  as  we 
saw,  was  changing.  The  fruit-bearing  trees  were 
coming  in,  and  there  were  presently  immense  stores 
of  rich  food,  apart  from  insects,  in  the  shape  of  nuts. 
Until  carnivores  learned  to  climb  trees,  this  was  a 
very  safe  and  satisfactory  world  to  live  in.  A  very 
large  family  of  the  primitive  insect-eating  and  tree- 
climbing  mammals  remained  in  the  trees,  and 
prospered.  While  the  horse  was  developing  on  the 
plains  of  America,  and  the  hippopotamus  in  the 
swamps  of  Africa,  the  monkey  family  was  evolving  in 
the  trees,  all  unconscious  of  the  remarkable  destiny 
of  one  of  its  branches.  Here  we  naturally  open  a 
new  chapter. 


CHAPTER  X 

THE  ORIGIN  OF  MAN 

Monkeys  have  always  had  a  strange  fascination  for 
men.  More  than  one  tribe  that  Hved  among  them 
has  puzzled  over  that  queer  suggestion  of  humanity 
which  they  seem  to  have,  and  declared  that  they 
must  be  human  beings  who  had  fallen  from  grace. 
By  the  end  of  the  eighteenth  century  it  was  openly 
suggested  in  England  that  man  had  "descended" 
from  an  animal  of  the  kind.  There  were  jeers  and 
jibes  and  hov^rls  of  laughter  everywhere.  Learned 
men  and  unlearned  scoffed.  Now  there  is  not  a  man 
of  science  in  the  world  who  does  not  admit  man's 
descent  from  an  ape-like  form;  and  I  do  not  think 
that  there  is  now  a  bishop  in  the  world  who  would 
oppose  them.     So  let  us  not  laugh  too  loudly  at  new 

ideas. 

It  is  usual  to  explain  very  carefully  that  man  has 
not  been  evolved  from  a  monkey  or  an  ape .  Certainly 
no  existing  monkeys  or  apes  are  in  the  line  of  man's 
ancestry.  There  are  in  each  case  certain  structural 
differences  which  forbid  us  to  suppose  it.  The  Dutch 
are  not  descended  from  either  us  or  the  Germans. 
They  are  related  to  us  and  the  Germans  through  a 

105 


io6  THE  ORIGIN  OF  MAN 

common  ancestral  tribe  of  some  thousands  of  years 
ago.  They  are  remote  cousins  of  ours.  So  the  living 
apes  and  monkeys  are  related  to  us  only  through  a 
common  ancestral  tribe  of  three  or  four  million  years 
ago.  They  are  remote  cousins.  Thoughtless  people 
sometimes  ask  why  we  cannot  turn  a  man-like  ape 
into  a  man.  They  never  ask  whether  we  could  turn 
a  negro  or  a  Red  Indian  into  a  white  European.  Yet 
the  white  and  black  and  red  men  had  a  common 
ancestor  probably  less  than  quarter  of  a  million 
years  ago,  whereas  it  is  certainly  much  more  than  a 
million  years,  possibly  two  or  three  million  years, 
since  the  common  ancestor  of  the  ape  and  the  man 
lived. 

The  difficulty  that  some  people  still  have  in 
imagining  the  descent — it  would  be  better  to  say 
"ascent" — of  man  from  an  ape-like  form  of  long  ago 
is  caused  by  the  foolish  habit  of  contrasting  themselves 
with  a  gorilla  or  an  orang.  There  is  about  themselves 
a  dignity,  a  wisdom,  a  virtue  that  are  lamentably 
absent  from  the  gorilla.  But  if,  instead  of  taking 
that  finished  product  of  human  evolution,  ourselves, 
we  adopt  the  more  sensible  course  of  taking  a  lower 
type  of  human  being,  the  argument  grows  thinner. 
After  all,  it  is  not  we  who  descended  from  an  ape-like 
form;  it  is  our  remote  ancestors.  We  descended  from 
them.  So  let  us  get  as  near  as  we  can  to  our  ancestors. 
The  Australian  black  takes  us  a  long  way.  I  have 
seen  Australian  aboriginal  "ladies"  who  would  not 


THE  ORIGIN  OF  MAN  107 

be  so  very  disdainful  of  an  orang.  Yet  these  are  not 
half-way  back  to  our  ancestors.  Some  of  the  central 
African  natives  take  us  still  further.  Take  the  ugliest 
and  most  stupid  of  these  that  you  can  find,  imagine 
something  far  more  ugly  and  stupid,  and  then  you 
have  our  human  ancestor.  We  have  various  skulls 
of  him,  and  we  know  it.  He  goes  very  near  the 
higher  ape-family. 

But  even  we  highly  civilized  and  refined  folk  have 
in  our  bodies — some  day,  perhaps,  scholars  will  say 
in  our  characters  (wars,  cruelties,  etc.)  also— many 
traces  of  our  brute  ancestry.  Why  has  the  male 
human  being  got  breasts?  He  has  real,  though 
stunted,  milk-glands  behind  those  little  warts  or  teats 
that  you  see.  Why?  Evolution  alone  gives  the 
answer.  We  come  of  a  very  ancient  group  of  animals, 
in  which  the  male  helped  to  suckle  the  young.  Why 
have  we  those  shrivelled  pieces  of  cartilage  which  we 
call  our  ears  ?  They  have  no  functions.  They  do  not 
help  you  to  hear.  Evolution,  and  evolution  alone, 
answers  the  question.  We  come  of  a  remote  animal 
ancestor  which  had  movable,  pointed,  useful  ears  like 
those  of  the  horse.  There  are  about  a  hundred  organs, 
or  parts  or  traces  of  organs,  in  the  human  body  to-day 
that  can  be  explained  only  in  this  way. 

We  come  of  a  remote  animal  ancestor.  What  was 
it  like,  and  how  and  why  did  it  become  man  ?  I  have 
said  that  it  is  now  customary  to  explain  very  carefully 
that  our  ancestor  was  not  a  monkey  or  an  ape.    1  con- 


io8  THE  ORIGIN  OF  MAN 

fess  that  I  think  this  caution  is  overdone.  It  is  a 
concession  to  the  spiritual  police.  If  we  had  the  re- 
mains of  man's  ancestors  before  us,  they  would  almost 
certainly  be  classed  as  those  of  monkeys  in  the  earlier 
stage  and  apes  in  the  later.  Possibly  some  of  them 
are  actually  among  the  existing  fossils. 

On  this  point,  however,  there  is  some  dispute  among 
men  of  science.  There  are  those,  possibly  the  ma- 
jority, who  would  look  for  man's  last  pre-human 
ancestor  in  some  branch  of  the  family  of  large  man- 
like apes  which  spread  over  the  region  of  the  Mediter- 
ranean between  a  half-million  and  a  million  years 
ago  (to  use  a  common  scale).  Certain  branches  of 
this  family  became  the  gibbons,  gorillas,  orangs,  and 
chimpanzees.  Other  branches  died  out.  One  branch 
became  the  human  race. 

Other  scientific  men  would  place  the  departure  from 
the  ape-world  much  further  back.  Professor  Keith 
one  of  the  most  recent  authorities,  thinks  that  the 
branch  of  the  arboreal  animals  which  was  to  become 
man  separated  from  the  main  stem  before  the  man- 
like apes  were  developed.  He  looks  for  a  common 
ancestor  of  the  primitive  htunans  and  the  primitive 
apes  something  like  two  million  years  ago.^  This 
common  ancestor  was,  however,  of  a  monkey-type, 
a  branch  of  the  very  large  simian  world  of  the  time. 
But  a  more  recent  writer  has  maintained  that  the 

^  See  the  excellent  genealogical  trees  in  his  A  ntiguity  oj  Man 
(I9I5)»PP-  508  and  509. 


THE  ORIGIN  OF  MAN  109 

whole  family  of  lemurs,  monkeys,  and  apes  have  such 
differences  of  structure  from  man  that  they  must  be 
regarded  as  separate  developments.  In  other  words, 
man  has  a  very  remote  common  ancestor,  of  three  or 
four  million  years  ago,  with  the  lemurs,  monkeys,  and 
apes;  but  our  ancestor  never  passed  through  any  of 
those  stages.  These  writers,  of  course,  hold  that  man 
was  evolved  from  a  primitive  mammal,  but  that  his 
ancestors  were  not  at  any  time  so  close  to  the  monkeys 
as  to  run  the  risk  of  being  classified  with  them. 

I  am  only  mentioning  these  theories  for  the  infor- 
mation of  the  reader.  The  grounds  of  them  do  not 
seem  to  me  convincing,  and  I  will  follow  the  usual 
view.  This  is,  shortly,  that  a  branch  of  the  primitive 
insect-eating  mammals  remained  in  the  trees  after 
the  Chalk  Period,  when  most  of  the  others  descended 
upon  the  freer  earth.  They  developed  in  the  direction 
of  the  monkeys;  whether  through  the  lemur  stage,  or 
whether  the  lemurs  are  (as  seems  probable)  a  side- 
line, we  need  not  inquire  here.  Tv/o  or  three  million 
years  ago  an  enormous  family  of  monkeys  spread  over 
Europe  (as  far  north  as  central  England),  Asia,  and 
Africa;  and  a  branch  passed  into  America.  One 
section  of  this  family  became  the  man-like  apes,  and 
man's  ancestors  must  have  been  so  closely  related  to 
these  apes  that,  if  one  were  produced  to-day,  we  would 
superficially  pronounce  it  a  man-like  ape. 

But  how  or  why  did  our  branch  of  the  family  get 
that  increase  of  brain  which  was  the  beginning  of 


no  THE  ORIGIN  OF  MAN 

human  development?  Most  people  think  that  this 
is  a  very  difficult  question,  because  they  have  a  very 
exaggerated  idea  of  the  increase  of  intelligence  that 
was  necessary.  They  never  ask  us  how  or  why  the 
man-like  apes  got  their  increase  of  intelligence  over 
the  ordinary  monkeys.  Yet  it  is  probable  that  the 
earliest  man  did  not  surpass  the  chimpanzee  in 
brain-power  more  than  the  chimpanzee  surpassed 
the  monkey.  The  earliest  human  skull  that  we  have 
may  be  400,000  or  500,000  years  old.  But  man  had 
then  been  developing  for  hundreds  of  thousands  of 
years.  Unless  you  suppose  that  he  was  strangely 
unprogressive  during  all  that  time,  you  are  forced  to 
recognize  earlier  stages  in  which  his  brain  was  not 
superior  to  that  of  a  man-like  ape;  for  the  earliest 
man  we  know,  the  product  of  ages  of  evolution,  is 
below  the  level  of  the  lowest  existing  savage. 

We  will  not,  however,  waste  time  on  considerations 
of  this  kind.  The  scientific  authorities  of  the  world, 
belonging  to  the  various  branches  of  science  which 
touch  this  question,  have  long  been  quite  unanimous 
that  man,  body  and  mind,  was  evolved  in  this  way. 
If  there  are  any  persons  who  like  to  call  into  question 
a  statement  on  which  all  the  scientific  authorities  in 
the  world  are  agreed,  I  can  only  say  that  England  is 
a  free  country;  but  I  do  not  care  to  argue  with  such 
people.  Man,  with  an  ape-like  body,  got  some  slight 
increase  of  brain  which  natural  selection  began  to 
foster.     How  did  he  get  it? 


THE  ORIGIN  OF  MAN  in 

It  is  generally  agreed  now  among  the  experts  that 
leaving  the  trees  and  beginning  to  live  on  the  ground 
is  enough  to  give  our  branch  of  the  family  an  advan- 
tage. Of  the  four  man-like  apes  three  live  to  some 
extent  on  the  ground,  and  some  even  use  their  hands 
to  help  them  along.  The  fourth,  the  gibbon,  is  much 
more  of  an  arboreal  animal.  It  is  very  unlike  man, 
and  not  particularly  intelligent,  but  it  may  interest 
us  here  for  two  reasons:  it  can  stand  upright,  and  it 
is  extraordinarily  active  in  the  trees.  Of  course,  it  is 
not  in  the  line  of  our  ancestry,  but  some  of  the  best 
authorities  think  that  man's  ancestor  was  probably 
very  active  like  the  gibbon.  If  you  have  seen  a  gibbon 
in  its  cage  at  the  Zoological  Gardens,  you  must  have 
noticed  its  prodigious  leaps  and  untiring  activity. 

Now,  it  is  supposed  that  our  branch  of  the  family 
quitted  the  trees.  It  has  been  suggested  that  perhaps 
our  ancestors  lived  in  forests  in  certain  parts  of  Asia, 
and  that,  owing  to  the  rise  of  the  land  and  increasing 
dryness  of  the  atmosphere,  the  forests  disappeared. 
Many  reasons  could  be  imagined.  In  any  case,  you 
will  have  no  difficulty  in  seeing  that  such  a  descent 
from  the  trees  would  sharpen  the  wit.  On  the  ground 
a  sharper  watch  must  be  kept  for  enemies.  The  hunt 
for  food  is  more  exacting  than  among  nut  and  fruit- 
bearing  trees.  The  back  legs  bear  the  weight  of  the 
body  more  and  more.  The  hands  are  used  more  and 
more  as  hands.  Physiologists  work  out  the  effect  on 
the  brain  of  all  these  changes,  and  they  tell  us  that 


112  THE  ORIGIN  OF  MAN 

the  new  life  would  stimulate  the  brain.  If  you  allow 
at  least  half-a-million  years  to  reach  the  level  of  the 
lowest  savage  from  the  level  of  the  chimpanzee,  you 
will  realize  that  this  suffices;  and  in  spreading  the 
progress  over  that  long  period  you  are  assuming  a 
rate  of  improvement  of  intelligence  immeasurably 
slower  than  we  have  actually  witnessed  in  the  last 
hundred  and  fifty  years. 

It  is  really  the  slowness  of  man's  early  evolution 
that  puzzles  us.  I  have  on  an  earlier  page  mentioned 
a  prehistoric  human  skull  that  was  found  at  Piltdown, 
in  Sussex,  in  191 1.  It  must  have  been  buried  some- 
thing like  400,000  years  ago.  There  has  been  a  great 
deal  of  controversy  about  this  skull,  as  parts  are 
missing,  and  it  is  possible,  in  reconstructing  it,  to 
make  the  forehead  slope  back  like  that  of  a  gorilla  or 
stand  up  like  that  of  a  modern  man.  From  this 
single  skull,  therefore,  we  will  not  draw  any  firm 
conclusion.  But  the  jaws  were  undoubtedly  brutal 
and  retreating,  the  teeth  bulging;  and  the  majority 
of  the  authorities  concluded  that  it  was  the  skull  of  a 
man  very  low  down  in  the  scale  of  intelligence.  As 
all  the  other  prehistoric  skulls  of  early  date  are  of  the 
same  character,  we  have  a  fair  idea  of  our  ancestor  of 
between  a  quarter  and  half-a-million  years  ago.  ^ 

'  This  is  questioned  by  Professor  Keith  and  those  who  make 
the  "Sussex  man "  highly  developed  in  brain.  They  think  that 
there  were  two  human  races  at  the  time,  a  higher  and  a  lower,  and 
they  put  the  real  origin  of  man  much  further  back,  as  I  said. 


THE  ORIGIN  OF  MAN  113 

And  the  stone  implements,  which  we  have  recovered 
in  millions,  confirms  this.  Whatever  dispute  there 
may  be  about  skulls,  the  stone  implements  tell  a 
plain  story  of  gradual  evolution.  They  are  at  first 
so  poor  that  experts  could  not  agree  for  years  whether 
they  had  been  touched  by  the  hand  of  man  or  whether 
their  shape  was  purel}^  accidental.  These  are  called 
"Eoliths."  The  next  and  largest  class  of  stone  im- 
plements, those  which  belong  to  the  Old  Stone  Age, 
begin  with  crudely  chipped  flints,  and  gradually 
pass,  in  the  course  of  perhaps  a  quarter-of-a-million 
years,  to  rather  skilfully  shaped  hand-axes,  scrapers, 
chisels,  etc.  They  seem  to  make  it  impossible  for  us 
to  think  that  there  were  two  races,  a  higher  and  a 
lower,  half-a-million  years  ago.  Indeed,  only  a  few 
of  the  crudest  flints  (if  any)  go  back  to  that  remote 
period,  yet  man  had  then  already  been  on  the  earth 
for  ages.  Thus  from  the  stone  implements  we  gather 
that  for  ages  man  was  too  low  in  intelligence  even  to 
shape  stones  for  his  use  as  tools  and  weapons.  He 
probably  used  sticks.  Then  for  further  hundreds  of 
thousands  of  years  he  was  still  too  low  to  conceive 
the  idea  of  making  handles  for  his  implements,  or 
making  the  bow  and  arrow,  and  merely  made  such 
progress  as  a  poor  type  of  savage  might  in  the  shaping 
and  finer  touching  of  his  stones.  It  is  a  story  of  most 
extraordinarily  slow  progress  in  intelligence. 

Putting  together  the  bones  and  the  stones,  we  can 
fairly  reconstruct  the  story  of  early  man.     For  some 

8 


114  THE  ORIGIN  OF  MAN 

reason  or  other  a  branch  of  the  ape-like  tree-climbers, 
as  active  as  gibbons  but  as  intelligent  as  orangs,  left 
the  trees.  The  busier  and  more  vigilant  life  on  land 
sharpened  their  wit  a  little,  and  they  entered  upon 
the  long,  slow  road  of  evolution  of  intelligence.  They 
lived  in  small  family  groups,  as  the  man-like  apes 
do;  not  social  groups.  At  first  they  may  have  helped 
themselves  along  with  their  knuckles,  as  gorillas  do; 
but,  if  they  were  already  as  nearly  erect  as  gibbons, 
they  would  be  able  to  use  the  hands  more  and  more 
for  grasping  purposes.  Sticks  would  be  their  natural 
weapons;  but  throwing  stones,  and  eventually  hitting 
their  enemy  with  large  stones,  would  not  be  a  very 
advanced  step  to  take.  Various  kinds  of  monkeys  do 
this.  The  human  touch  began  when  this  primitive 
creature  first  knocked  two  flints  together  to  give  one  of 
them  a  sharper  edge.  The  age  of  "Eoliths"  opened. 
It  seems  probable  that  the  cradle  of  the  race  was 
in  the  region  of  the  south-west  of  Asia.  A  great  deal 
of  land  foundered  about  that  time  in  what  is  now  the 
Indian  Ocean.  Probably  the  region  of  man's  evolu- 
tion was  part  of  this  lost  continent,  the  last  remnant 
of  the  continent  which,  we  saw,  at  one  time  connected 
Asia  with  Africa  and  Australia.  It  is  significant  that 
we  find  our  earliest  human  remains  in  the  island  of 
Java.  In  the  collection  of  prehistoric  remains  at 
South  Kensington  you  will  find  a  skull  marked  the 
Pithecanthropus,"  found  in  Java.  The  name  means 
Ape-Man,"  and  the  specimen  is  so  labelled  in  every 


<< 


(( 


THE  ORIGIN  OF  MAN  115 

collection  in  the  world.  It  tells  its  own  sto^3^  These 
bones  belonged  to  a  creature  which  was  half  ape  and 
half  man,  or  midway  between  the  higher  apes  and  the 
lowest  savages.  As  a  matter  of  fact,  scientific  men 
at  first  disputed  very  warmly  whether  they  were  the 
bones  of  an  ape  or  a  man.  We  now  admit  definitely 
that  they  are  human,  and  that  they  do  not  even  repre- 
sent the  earliest  human  phase.  Man  had  already 
been  evolving  for  hundreds  of  thousands  of  years. 
But,  of  course,  the  Java  branch  of  the  family  have  re- 
mained stationary,  as  isolated  tribes  do.  The  bones 
in  that  case  really  represent  a  much  earlier  phase  of 
htunan  evolution,  and  are  most  interesting.  The 
thigh  bones  are  curved,  the  teeth  projecting,  and  the 
skull  extremely  low  in  the  scale  of  intelligence. 

We  have  a  dozen  skulls  and  jaws  representing  the 
next  chief  phase — man  of  the  Old  Stone  Age.  The 
Piltdown  skull  seems  to  belong  to  quite  the  earliest 
part  of  it,  and  is  very  valuable.  Other  skulls  found 
in  France,  Belgium,  and  Germany  show  various 
stages  in  the  long  journey  upward.  Man  was  still, 
after  half-a-million  years  development,  below  the 
level  of  the  Australian  black.  The  skull  of  an  Aus- 
tralian black  grimly  watches  me,  in  my  study,  as  I 
write  this.  It  is  quite  respectable  in  comparison 
with  some  of  the  prehistoric  skulls  I  have  examined. 
The  man  of  the  Old  Stone  Age  had  a  low,  retreating 
forehead,  brutal  jaws,  and  a  robust  but  not  tall  frame. 
He  wore  no  clothes,  but  had  still  a  thick  coat  of  hair 


ii6  THE  ORIGIN  OF  MAN 

over  most  of  his  body.  All  his  implements  were 
carried  and  used  in  the  hand,  without  handles,  and 
he  had  no  bow  and  arrow.  He  had  no  home.  The 
climate  was  still  so  good  that  the  rhinoceros  and 
hippopotamus  and  elephant  wandered  over  Britain 
with  him.  He  lived  in  family  groups,  not  social 
groups.  He  was  still  subject  only  to  the  very  slow 
and  cumbrous  evolutionary  method  of  natiiral  selec- 
tion— the  struggle  for  food  and  life  and  survival  of  the 
fittest.  Had  he  remained  subject  only  to  this  law  of 
progress,  we  might  all  to-day  be  at  the  level  of  the 
Zulu.  But  natural  selection  now  took  on  its  grimmest 
form,  an  Ice  Age,  and — something  happened. 


CHAPTER  XI 

SOCIAL   EVOLUTION 

Let  us  glance  back  for  a  moment  at  the  course  of  our 
story.  During  the  first  half  of  it,  which  we  crushed 
into  a  few  pages,  life  had  not  got  beyond  the  stage 
of  the  worm,  the  shell-fish,  and  the  star-fish.  Twenty, 
if  not  fifty,  million  years  were  used  up  in  this  poor 
advance.  Let  us,  for  the  sake  of  being  clear,  give  a 
definite  number  of  years  to  the  story  of  life — say, 
fifty  million  years,  though  it  was  probably  much  more. 
On  that  scale  it  took  thirty  million  years  for  life  to  rise 
to  the  level  of  the  fern,  the  beetle,  and  the  fish.  Seven 
or  eight  million  years  later  life  had  advanced  as  far 
as  the  first  reptile. 

Then  a  great  Ice  Age  occurred,  and  the  primitive 
birds  and  mammals  appeared.  But  there  was  a 
reaction,  and  for  seven  or  eight  further  million  years 
the  reptile  was  the  lord  of  the  earth,  and  the  mammal 
Made  hardly  any  progress.  Forty-five  million  years 
out  of  the  fifty  million  were  over  when  the  mammals 
began  to  spread.  Four  out  of  the  five  remaining 
million  years  were  over  before  the  very  lowly  and 
primitive  thing  that  we  can  just  call  man  came  on 

the  scene. 

117 


ii8  SOCIAL  EVOLUTION 

But  the  pace  of  progress  was  still  very  slow.  For 
at  least  three  quarters  of  a  million  years  man  made 
inconceivably  slow  advance.  For  most  of  the  time 
he  must  have  been  stationary.  Then  the  last  Ice 
Age  occurred,  and  we  shall  see  that  it  drove  men 
into  social  life.  Dates  are  difficult,  but  we  may  put 
this  development  of  social  life,  roundly,  about  fifty 
thousand  years  ago — to  take  the  end  of  the  Ice  Age 
and  the  full  term  of  its  influence.  Man  now  reached 
a  level  a  little  above  that  of  the  Eskimo.  The  pace 
was  now  much  faster.  Ten  thousand  years  ago  the 
foundation  stones  of  civilization  were  laid  in  Egypt. 
Five  thousand  years  ago  two  great  civilizations  had 
reached  a  high  development.  But  there  was  still 
something  wrong  with  the  machinery  of  evolution. 
Man  was  nominally,  but  not  thoroughl3^  social. 
There  was  no  social  sentiment  between  groups  of 
men — tribes  or  nations — and  horrible  wars  wasted 
their  resources  and  destroyed  their  lives.  Seven 
himdred  years  ago  Europe  was  in  most  respects 
lower  than  civilization  had  been  five  thousand  years 
before.  A  few  centuries  later  the  advance  was 
resumed.  A  hundred  years  ago  we  had  got  back  to 
the  general  level  of  ancient  Rome  and  Greece.  And 
in  the  last  hundred  years,  which  have  been  especially 
marked  by  the  growth  of  social  ideals,  we  have 
passed  every  previous  high-water  mark  of  civilization, 
and  have  made  more  progress  than  was  made  in  any 
five  hundred  years  in  the  history  of  man ! 


SOCIAL  EVOLUTION  119 

This  is  what  some  writers  on  science  and  social 
questions  (like  Mr.  Benjamin  Kidd)  forget — or  do 
not  know.  "Darwinian"  progress,  or  progress  by 
painful  struggle  and  natural  selection,  is  a  great 
fact.  But  it  is  a  description  of  the  past,  not  an  ideal 
of  the  present.  It  is  the  method  of  unintelligent 
nature,  costly  and  slow.  Darwin  himself — a  very 
gentle  and  humane  man —  drew  a  distinction  between 
"natural"  and  "artificial"  selection.  Natural  selec- 
tion we  have  seen  plenty  of.  Artificial  selection  is 
Vv^hen  man  breeds  new  species  of  pigeons  or  dogs  or 
sheep.  It  is  intelligent,  economical,  and  speedy.  It 
has  been  greatly  developed  in  our  time,  when  new 
fruits  and  flowers  are  created  speedily  and  cleanly,  as 
Luther  Burbank  does  in  California.  Darwin  would, 
of  course,  have  said,  if  you  had  asked  him,  that  to 
set  up  "nature's"  way  (that  is  to  say,  remember, 
unintelligent  nature's  blind  way)  as  a  model  for 
intelligent  man  would  be  the  height  of  absurdity. 
But  Darwin  shrank  very  naturally  from  politics — all 
social  work  was  "politics"  or  "Radicalism"  in  his 
time — and  was  concerned  only  with  the  past  or  with 
non-human  nature.  Darwinism  has  not  the  slightest 
bit  of  hostility  to  social  idealism.     It  has  nothing  to 

do  with  it. 

What  Darwin  did  not  know  as  well  as  we  do  to-day 
was  the  importance  of  social  evolution.  Dr.  Russcl 
Wallace  tried  to  show  this,  but  his  work  is  rather 
confused.     I  pointed  out  as  we  went  along  that  dur- 


120  SOCIAL  EVOLUTION 

ing  the  overwhelmingly  greater  part  of  the  story  of 
life  there  was  no  social  evolution  at  all.  Social  life 
was  found  only  among  sponges  and  corals  and  other 
unconscious  or  barely  conscious  types  of  animals, 
and  they  made  no  progress  during  millions  of  years. 
Social  life  proper  began  only  in  the  last  two  or  three 
million  years.  There  is  no  proof,  in  fact,  that  it 
began  earlier  than  within  the  last  million  years. 
At  all  events,  beavers,  bees,  ants,  etc.,  began  their 
social  ways  in  only  quite  recent  geological  time.  So 
the  "Darwinian  factor"  has  been  the  chief  agency 
of  evolution  during  forty-eight  out  of  fifty  million 
years. 

In  Darwin's  time  very  little  was  known  about  pre- 
historic man.  Now  we  know  his  story  very  fairly. 
I  have  described  the  early  part  of  it:  a  period  of 
non-social  life  and  extraordinarily  slow  progress. 
Curiously  enough,  many  advanced  social  writers 
insist  on  regarding  early  man  as  social  almost  from 
the  start.  They  probably  think,  that  this  explains 
his  progress;  and  they  would  change  their  opinion, 
which  is  a  pure  theory,  if  they  knew  how  very  little 
progress  man  made  for  three-quarters-of-a-million 
years.  The  facts  are  all  the  other  way.  The  man- 
like apes,  early  man's  cousins,  are  not  social.  They 
live  generally  in  families.  The  lowest  living  human 
groups  to-day  are  imperfectly  social.  They  live  in 
family  groups,  with  strict  monogamy,  and  have  no 
tribal  organization.     And,  as  far  as  we  can  gather 


SOCIAL  EVOLUTION  121 

from  the  pre-historic  remains,  early  man  was  not 
social,  and  did  not  live  in  groups  until  the  Ice  Age. 
So  we  may  fairly  infer  that  the  clan  or  tribe,  the 
social  group,  was  formed  by  the  clinging  together  of 
families,  not  the  family  evolved  out  of  the  social 
group;  and  that  this  occurred  late. 

Now,  the  geological  record  throws  a  very  important 
light  on  this.  During  all  that  long  period  when  early 
man  was  merely  creeping  upward,  so  to  say,  the 
climate  of  Europe  was  much  warmer  and  better  than 
it  is  to-day.  At  first  it  was  like  the  climate  of  Algeria ; 
later  like  the  climate  of  Australia.  Men  had  plenty 
of  primitive  food,  and  no  need  for  fire,  clothing,  or 
houses.  But  it  was  again  growing  steadily  colder. 
All  the  great  mountain  chains  of  our  world  were  rising, 
and  when  they  reached  their  culmination  a  great 
Ice  Age  set  in.  Five  times  in  succession,  with  com- 
paratively warm  periods  between,  a  sheet  of  ice  and 
snow  spread  from  the  mountains  over  Europe  and 
North  America;  and  there  were  other  sheets  wherever 
there  were  high  mountains.  At  the  fourth  and  great- 
est spread  of  the  ice-sheet  Europe  was  glacial  as  far 
south  as  the  Thames  and  the  Danube,  and  America 
as  far  south  as  St. Louis  and  New  York. 

The  pre-historic  inhabitants  of  Europe  were  driven 
south,  and  forced  to  live  in  caves.  No  doubt  rock 
shelters  would  be  used  at  first,  and  men  would  gradu- 
ally venture  into  the  dark  caverns.  We  find  groups 
huddling  in  the  caves  of  Derbyshire,  and  very  large 


122  SOCIAL  EVOLUTION 

groups  living  in  the  caverns  of  the  south  of  France  and 
the  Pyrenees.  We  find  that  they  now  begin  to  make 
clothes  out  of  skins.  You  can  see  in  the  British 
Museum  to-day  some  of  the  bone  needles  they  made 
and  used.  They  learn  how  to  strike  fire  from  flint. 
They  develop  a  skill  in  art;  and  towards  the  close  of 
this  ''cave  period"  w^e  find  quite  clever  carvings  in 
ivory  (tusks  of  miammoth),  and  drawings  on  stone, 
bone,  and  ivory.  In  short,  the  pace  of  human 
progress  was  enormously  quickened  dtuing  the 
coldest  period  of  the  Ice  Age,  and  it  was  virtually  a 
new  race  that  spread  over  Europe  when  the  ice  and 
snow  disappeared. 

Social  evolution  had  begun.  Families  were  forced 
to  live  together  by  the  very  nature  of  their  new 
homes.  This  would  lead  to  greater  and  greater  efforts 
to  communicate  with  each  other.  From  the  struc- 
ture of  the  jaws  of  man  before  the  Ice  Age  we  can 
fairly  gather  that  he  had  no  articulate  speech.  Lan- 
guage of  a  crude  kind  seems  to  have  been  evolved 
in  the  caverns.  Men  could  exchange  ideas,  to  some 
extent;  and  the  clash  or  contrast  of  different  cultures 
is  the  great  secret  of  human  progress.  "Struggle"  is 
necessary.  But  those  who  think  that  it  must  be  a 
struggle  of  weapons  and  muscles,  or  of  greed  and 
selfishness,  are  hopelessly  unscientific.  The  struggle 
of  ideas  and  ideals  in  a  perfectly  harmonious  group 
is  enough. 

The  main  advantage  of  social  life  and  communica- 


SOCIAL  EVOLUTION  123 

tion  is  that  it  greatly  helps  the  weaker  in  intellect  to 
rise.  The  man  of  poor  mind  can  share  the  ideas  and 
discoveries  of  the  genius.  The  race  rises  as  a  whole, 
so  that  after  the  Ice  Age  we  are  not  surprised  to  find 
rapid  progress.  The  stimulus  to  progress  given  by 
social  life  would  be  checked,  as  long  as  the  hard 
conditions  lasted,  by  the  desperate  struggle  for  food 
and  warmth.  The  new  increase  of  intelligence  helped, 
because  it  created  better  weapons — the  spear,  bow 
and  arrow,  hafted  axe,  etc. — but  the  severity  of  the 
conditions  would  tend  to  distract  and  absorb  energy. 
When  the  last  ice-sheet  had  melted,  and  Europe 
recovered  at  least  the  degree  of  warmth  it  has  to-day, 
the  new  race,  the  men  of  the  New  Stone  Age,  spread 
over  it.  In  this  the  stimulus  to  progress  was  partly 
checked.  Tribes  lost  all  communication  with  others, 
and  stagnated.  Progress  would  be  most  in  the  south, 
where  groups  were  nearer  each  other. 

I  am,  of  course,  neglecting  the  greater  part  of  the 
human  family  in  this  sketch.  No  doubt  it  had  been 
distributed  over  the  earth  before  the  Ice  Age,  but  it 
was  chiefi}^  the  branch  of  the  family  which  turned 
towards  Europe  that  experienced  the  full  stimulation 
of  the  Ice  Age.  During  the  greatest  extension  of  the 
ice-sheet  this  branch  of  the  race  would,  to  a  large 
extent,  retreat  south,  across  the  land  bridges  to 
North  Africa  and  Asia  minor.  There  would  be  a 
relatively  thick  population  from  the  Persian  Gulf  to 
Algeria,  and  this  would  be  thickest  from  the  Persian 


124  SOCIAL  EVOLUTION 

Gulf  to  Egypt,  where  there  was  most  depth  of  country. 
Just  about  this  time  the  valley  of  the  Nile  and  the 
valley  which  we  call  Mesopotamia  were  formed  by  the 
rivers;  and  out  of  the  turmoil  and  struggle  of  tribes 
for  the  fertile  valleys  came  the  first  beginnings  of 
civilization. 

The  story  of  evolution  is  a  great  aid  to  correct  think- 
ing. It  may  begin  with  stars  which  are  a  long  way 
off,  but  it  leads  to  man  and  man's  evolution.  It 
gives  you  a  solid  scientific  ground  for  hope  and  trust 
in  man.  No  evolutionist  can  be  a  pessimist.  The 
human  story  is  only  just  opening.  Those  million 
years  of  early  human  development,  of  which  I  have 
spoken,  were  only  the  prelude.  Now  we  know  more 
or  less  where  we  are  and  what  we  are  doing.  Ac- 
cording to  the  best  estimates  of  mathematicians, 
man  will  remain  on  this  earth  for  something  more 
than  ten  million  years  yet.  At  the  rate  at  which  we 
have  gone  for  the  last  hundred  years,  this  period  of 
time  opens  out  a  prospect  of  such  happy  developments 
as  are  beyond  the  capacity  of  the  liveliest  imagina- 
tion. We  are  the  factors  of  evolution  to-day.  We 
are  the  masters  and  the  creators.  Let  us  get  the  plan 
right  and  forge  ahead. 


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What    Is    Man? 

By 

J.  Arthur  Thomson,  M.A.,  LL.D. 

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Editor  of  **  The  Outline  of  Science  " 

The  proper  study  of  mankind  is  Man,  and  this 
bcok  is  an  introduction  to  the  study.  It  is  written 
mainly  from  the  biological  point  of  view,  but 
other  aspects  are  not  left  unconsidered.  It  is  not 
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Human  Mind,  Man  as  a  Social  Person,  Human 
Behavior  and  Conduct,  Variability  and  Inertia, 
Sifting  and  Winnowing  in  Mankind,  the  Contact 
and  Conflict  of  Races,  Shadows  and  Disharmonies, 
and  Possibilities  of  further  Evolution.  It  ends 
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